As a warrior, you need to combine warrior skills with skills from other categories. Also there are some choices u absolutely have to make.
U have to pick lockpick up to 5. (gradually)
Forget mindreading, and forget wisdom. U get some trinkets as well that can boost and enable these skills when u have to. (Later on u may even be able to liberate 1 point in mindreading to use it elsewhere, and mindread with the help of a trinket that u put on when u have to). Same goes for wisdom, but u really don't need it if u play through the side quests. Also, at later stages, you won't be able to go much more than level 35 if at all. There are few people u need to mindread in the game, the reductions in xp cost are puny, and u get more than enough xp, etc. If u get too high level, the enemies cant hurt u at all! not even one hitpoint, and they only need to be a couple opf levels below you.
Forget encumbrance, just sell ur stuff, don't be a hoarder.
WIth the skillpoints u get from mindreading and quests u might gt in total 40-45.
This means u have only space for 4 skills to the maximum of 10 (incraesed from 5 later on in the game), and if u wanna hurt a highlevel character u have to do with it a powerful skill.
Must start by maxing out dual wield or one-handed. A must. Dual wield is rally for mages, so go for one-handed - fancier weapons.
At first invent a point in hideinshadows to sneak up on enemy and polymorph to turn enemies into butterflies (very useful against bosses), but u may as well wait for trinkets that do that.
In the middle of the game u will have a chance to rearrange ur skillpoints. So u have some freedom.
Regenerate - automatic health recovery. As a warrior u will be stuck a lot of times waiting for your health to regenerate, either speed it up or endure it. Ur choice.
At first u will have to invest in the lower warrior skills (in the skills treee) but later, u will need to reassign all the points u have into the highest skills - such as thousand strikes and battle rage.
To be honest, warrior skills are a bit of a mess, only whirlwind and battle rage, and thousand strikes and regenerate make any sense really.
If things get tough, get backup from ur creature. But (not sure) I think creatures and summoned ones steal your experience.
Overall, as a warrior, it's going to be tough.
For more guidance - game maps, walkthrough, faq -
http://guides.gamepressure.com/divinityiiegodraconis/guide.asp?ID=8297.If u r still stuck - use the forum.