The key is learning how to learn. Allow yourself time to read, practice, fail, and get up and try again!!!
This is one job where you get paid to make mistakes and fail, and make more money from learning what you did right, and knowing what you did wrong. You make even more money from passing on what you have learned.
So study, read all you can about writing effective ads, and practice, experiment away!!!
Best of Luck you my friend and co-worker!