For Contribution points: Cooking beer and essence of liqour to get side products you can turn in for CP.
For combat exp: For combat exp you got 2choices 1 go to a spot with alot of exp and lvl faster or go to a spot that gives more money which in the end is more important.

i personally always grind at Gahaz Bandits cause the money there is great and the exp is decent aswell. however if your gear is a bit on the lower side you might want to choose to go to desert fogans instead.

For Skill points: i do 2 things for skillpoints i use the afk training books when  i go to sleep and i grind fast and easy mobs like fogans or gahaz(yes i know i love gahaz :D )

you can also choose to become a lifeskiller: this however takes a lot of time and effor compared to what ppl generally think. i personally only do imperial trading and crates.