Complete quests to get stronger and level up or eat if you are a hollow. You get a skill point for every level which can be used in the skill tree to obtain new skills and passives. Equip new skills by opening up your inventory which is in your menu.
[Controls]
M - Menu
LMB - M1
RMB - M2
F - Block
Q - Dash
P - Meditate
V - Charge Reiatsu
No Comment.