Before we go into this, I'll just say now that this is intended for giants building with mostly a strength build. If you're for whatever reason rolling with vit or dex for your primary stat, this guide is not for you. As a strength primary build for both savages and berserkers have the highest and most practical potential, that's what this guide is going with.
Stat Spread
You only have 3 stats that you're ever going to have to worry about on your giant. Anything else is a complete and total waste. I'm not going to give you any cookie cutter 3/1, 2/1/1, numbers or anything like that. The best way to build a character, is to suit it to you and your playing style.
Strength - This should be your primary stat. The one you add the most too. Any excess points you have should go into strength to increase your base damage, and your critical damage, as well as your p.def. Your strength should always be your highest stat.
Vitality - As far as vitality is concerned, you will not need more than 1 per level at this stage of the game. All the way through 50 you can safely go with 1 vit per level. Or if you'd rather, you should be able to skip some of the vit, or go with very few, or no vit points at all to get more damage. If you feel squishy, or weak, and you have armor appropriate for your level, then I would suggest adding in some vit points.
Dexterity - You need dexterity to hit things as a melee class. There isn't a very reliable, or complete way to avoid this. For either the future savage, or berserker 50 dex on your way to level 50 should cover all your needs for accuracy. As a savage, the fewer points you spend in dex to get by, the better. For a berserker, you can stick with 50 dex for accuracy, unless you want to make use of your dex based polearm skills, in which case, you can add more if you'd like. Never make dex your primary stat though.
Accessories - Accessories with str, dex, or vit on them are good for your giant. Try to lean towards str and dex mostly though. For boss accessories in your early development there are a few options. Mix and match as you see fit. These can be a suitable alternative to adding dex for some of your accuracy issues.
Black Turpin Chain - Adds 10 str, 7 dex, 100 HP, Level Requirement 25. It's dropped by an archer mini-boss in black dragon sanctuary, who is either lvl 45 or 50. I forget his name, if someone could remind me that would be great.
Black Turpin Bracelet - Adds 10 dex, 7 str, 100 HP, Level Requirement 25. This is a reversal of the stats on the chain. I personally think the chain is a better choice, but you take what you can get. It's dropped by the same boss as above. Sometimes he won't drop either though.
Ahkma Pendant - Adds 10 dex, 7 vit, 10 ranged attack, Level Requirement 25. Dropped by makkitpew in either black dragon sanctuary or caronia's tomb (that I've confirmed) Also said to be dropped by the Kan mini-bosses in Ahkma it's not the best choice IMO but it's better than nothing if you want the dex.
Fierce Pendant - Adds 10 str, 7 vit, 10 melee attack, Level Requirement 25. Can likewise be obtained from the various Kan mini-bosses in Ahkma cave. This is a nice piece to have for any giant.
Ring of Prodigious Power - Adds 15 str, 5 vit, 10 melee, Level Requirement 35. These can be obtained from Mollek the minotaur sub-boss in Ahkma Cave. He's level 45, and rather painful considering his level. I believe these are very good accessories to have for your giant, maybe mixed with 1 Turpin chain or bracelet for some dex.
That pretty much covers the stat spread for levels 1-50 and the boss accessories available to you that are best suited to helping you out.
Skill Spread
Here's the lay-out for the warrior tree. So let's discuss what you need from it. This is directed towards an optimal build in saving as many points as possible for your second job.
A - Imbue - Pick one of them and only one. There are dozens of discussions on which are better and why. Frozen is good for PvP to keep people from running from you, Darkness is good to slow down attacks, and Divinity is good for keeping your mana up. I don't care which you take, or why, just take one. It will not make or break your character. Go with 1 level in it early on, but max it later when you have the mana to sustain the skill. It will account for 20% of all the damage you do. Worth 5 skill points right?
B - Blood Adrenaline - This is an optional skill. It's not very useful early on. However later, when you have high melee, it can give you a very large damage boost. Many players are concerned with the 30% HP loss, but I say, this is a skill you use in a situation where you have advantage. If you want this skill get it later, after your second job is reached when you have substantial melee to boost with it.
C - Taunt - You must get this to move into the rest of your tree, and it's not really a bad skill to have.
D - Bereave - This is an attack skill for dual-swords only. If you want an attack, skill I recommend only putting 1 point into it, and only if you are planning on going Savage. You can reach 50 without attack skills though, and save valuable skill points for better skills.
E - Battle Chant - You must put at least 1 point into this skill to get to the rest of your tree, and there's really no reason not to put in 5. It gives a very large HP boost based on your level. With 1 vit per lvl + battle chant 5 + base rolls (8 hp per lvl), it allows a giant to effectively gain 58 HP per level up. This is a recommended must have skill.
F - Reap - This is an attack skill for pole-arms only. If you want an attack, skill I recommend only putting 1 point into it, and only if you are planning on going Berserker. You can reach 50 without attack skills though, and save valuable skill points for better skills.
G - Find Hole - This skill is a bit redundant. Personally I see no room in it for a savage tree. I'm not sure about a berserker tree yet. However, to make use of it, you already have to have good accuracy. So at that point... why bother?
H - Rage - This skill nets you a ton of critical damage. It converts 160% of your str + 160% of your dex into added critical damage whenever you land a crit hit. Max it to level 5. Recommended must have skill.
I - Crush - Gives you a chance to open treasure chests without a key. Sounds nifty, but I get plenty of keys at my level. If you want it, go for it though, but you have to get reap to get to this skill. Only put it to level 1 since you can rebuff it and try again, and again, and again until you get your chest open. Thanks to Deathklaat for his input on this.
J - Power Surge - Another attack skill. It requires 1 pt in find hole to open it up. This looks like a strong skill, and it possibly is, but I think there are better choices in the Savage tree. It's for dual-swords only. Take it only if you're going Savage. Even then, I suggest only putting 1 pt into it until you have your best skills on your second job.
K - Life Force - Gives you a 50% chance to heal some HP everytime you're hit. This is a neat idea. However, in later levels I don't think this skill will be necessary, or practical. In PvP either the life it heals either just isn't worth worrying about, or it's not going to be enough to matter. In PvM, your HP should never really be an issue. You have to put 1 skill pt in this to open up better skills though.
L - Rampage - This is an optional attack skill for pole-arms. Take this skill only if you're going Berserker, and only then if you're going to add more to your dex than the recommended 50 for accuracy. This more points you add to this skill, the more you will get out of both it, and your dex points.
M - Shoulder Charge - This is a paralyze skill similar to the knight's rush. You will need this for PvP eventually. When you decide to take it is entirely up to you but max it when you do. It will not help you much at all in PvM, as bosses resist it, and mobs don't really require stuns. It is a recommended must have skill.
N - Brute Force - Increases your critical rate. This will help churn out extra crits which comboed with Rage amounts to huge damage. Max this skill. It is a recommended must have.
O - Kidney Strike - This skill is a DoT (damage over time) When you use it, it will hit as an attack skill and do normal damage. Then every 3 seconds for 15 seconds it will do 50% of whatever damage you did when you hit. Be it crit damage, or normal damage. If you want this skill, only put 1 point into it. It never gets stronger only lasts longer. I don't think it's that great for a Savage build, but a Berserker has high damage per hit, and a slower attack speed, they could make more use of this skill.
P - Giant Shift - This is an AOE attack that also reduces player stats temporarily in PvP. If you want an early AOE other than power surge, go for it. In the later game though, 25 stats means very little. As far as I know, those stats come off the players base stats, and they also temporarily lose any active buffs in relation to those 25 stats. So in most cases not even double the 25. The reduction lasts only 10 seconds. Not very worthwhile for a Savage in my opinion, as they get Rampage Force at 51. A berserker might like it if they have the room in their tree, for an extra AOE. Thanks to Krone for corrections on this skill.
That covers all the skills. So optimally, all you need your tree to look like is this...
