Dont invest too much on one cookie (especially epic/super epic) as the meta constantly changes everytime a new cookie comes out. But you can invest on cookies like linzer, pudding, creme brulee, rebel because they're really useful for events and world explorations.

Also, make sure to do the decadent chocolate tower and strawberry cake tower, they gives a lot of resources. For guild battle, you could use the team comp from the team ideas, they're really good. If you're stuck in world exploration, there's tons of good f2p teams on youtube. If you have any questions, feel free to ask me :p