Here is a rough overview of how to skill your character in Gothic 2 if you want to become a mercenary and subsequently a Dragonhunter and focus on wielding two-handed weapons, as well as a bow. Your focus is going to be dexterity and the ultimate goal is going to be having a total of:

160 Dexterity
94% Bow-skill
160 Strength
90% Two-Hand-Skill (you’ll get 10% temporary)
As well as a bunch of miscellaneous skills

The total level needed for this build is around 52.

Overview of the stats learned and gained through other means

Strength (160):

Chapter 1	Chapter 2	Chapter 3	Chapter 4	Chapter 5
10 Base		42 Training	26 Training	01 Thekla’s Stew
			01 Fire Stew	12 brewed Strength elixirs
			02 Dragonroot
			04 Apples
			01 Erol
			04 Thekla’s Stew
			09 Found & Bought Strength elixir
			01 Stew (Jharkendar)
			15 brewed Strength elixirs
			22 Stone tables
			10 Prayer

126 LP

Dexterity (160):

Chapter 1	Chapter 2	Chapter 3	Chapter 4	Chapter 5
10 Base	16 Training	01 Goblin berries	03 Goblin berries	~20 Goblin berries*
47 Training	02 Stone tables (Valley)	06 Found & Bought Dex elixir	04 Stone tables (Valley)
	06 Stone tables (Khorinis)		10 Prayer
	12 Stone tables (Jharkendar)
	01 Rengaru
	06 found Dex elixiris
	39 brewed Dex elixirs

111 LP

*Paladins have a chance of dropping Goblin berries or having them in their vendor inventory. You find a couple of dead Paladins in the valley, but you could theoretically kill or beat-up every single Paladin in the game for the maximum chance of getting berries, which is how you get to a number like that. If you do not do that, you should maybe get one or two on average.

2-handed weapon skill (90%+10% from weapon):

Chapter 1	Chapter 2	Chapter 3	Chapter 4	Chapter 5
10 Base	42 Training			13 Training
				05 Double Blocks
				20 Stone tables

87 LP

Bow (94%):

Chapter 1	Chapter 2	Chapter 3	Chapter 4
10 Base	18	04 Stone tables (Valley)	04 Stone tables (Valley)
11 Training		06 Stone tables (Jharkendar)
		16 Stone tables (Khorinis)
		25 Training

84 LP

Misc.:

Chapter 1	Chapter 2	Chapter 3	Chapter 4
Skinning animals (5 LP)	Elixir of Dexterity (20 LP)		Dragon blood (3 LP)
Stealth (5 LP)	Minecrawler plates (3 LP)		Elixir of Strength (20 LP)
Lockpicking (10 LP)	Shadow beast horns ( 3 LP)
Pickpocketing (10 LP)	Stone table language (30 LP)

109 LP

Total: 465 LP

Additional information:

The chapter order of some of the skills is not entirely mandatory. You could for example focus more on Two-handed skill and finish that up first, before going for Bow-skill. However some of the permanent bonuses (like Thekla’s Stew for example) are only available in the later chapters, so bear that in mind. Always make sure you have invested all the learning points into skilling before taking the permanent bonuses.

You are going to be a Dragon hunter which means you want to learn how to pull Shadow beast horns because there is going to be a quest to sell those to Buster on Onar’s farm. Each horn gives 300 EXP (as well as 350 gold) which realistically means that you are going to get those 3 LP back fairly soon. There are 9 Shadow beasts in Khorinis alone (more spawn in later chapters and you can also find some in Jharkendar and the Valley)

Minecrawler plates are entirely optional and only necessary if you want to get the armor (which is advisable in my opinion)

The other stuff is pretty much mandatory for completing the game or for say getting the Dragonhunter armor.

Also, make sure to have a properly optimized and enhanced Gothic 2 Installation with Spine