A little more information would help us out a lot for answers, including what (types of) spells you're wanting to use, and why.
Also, someone doesn't have to be "good at" a religion to practice it. Wicca is not necessarily a skill; it is a set of beliefs.
As for practicing magic, it takes a bit of work. Just not using it will not make it easier; looking into why there is trouble may find an answer, and focusing on specific things will help develop the skills you want.