How to level up skills?

[Ray]

I upgraded my armor with armor spheres and found it only increases defense so I was wondering how you go about leveling the skill level. For example the Harvest helmet has a Focus lvl 1 and I want to level that up.

[Rodi]

Skill is levelled by stacking multiple armor pieces and jewels with that skill. Armor upgrades only increase defense.
Edit: If you have a helmet with focus x1, for example, and then you wear a chest armor with focus x2 (like damascus beta chest armor), you will have focus x3.

[Himars-TT]

You can't technically "level up" skills, only get more pieces/decos with that same skill. For instance, for the Focus one, you'd have to equip another piece of equipment with the Focus skill on it, or you'd have to find a Focus decoration.

[Ubungtharion]

Heres a skill calculator so you can see how skills go together. Here is my current build.

http://honeyhunterworld.com/mhwb/?107,95,84,84,82,84,65,health,aff,0,0,0,0,90,0,0,86,86,0,68,68,86,96,68,0,96,96,0,3

Tenderizer decoration = weakness exploit
Steadfast decoration = stun resistance
Protection decoration = divine blessing
Vitality decoration = health boost