Need some advice...

I am currently in the midst of writing 4 books right now (the ideas just keep coming!) and I am facing difficulty finding the motivation to keep continuing. For example sometimes I feel like giving up because writing a book is a tedious process and i'm not very patient! Do any of you have tips to overcome this problem? Also, I am looking for some tips to guide me in my writing. Thanks in advance :)

P.S. I am actually very inexperienced (I'm only 12, turning 13 next year) and I also need to juggle between all my activities. Hope you all can help! :)