Ask away! We've all been where you are and we'd love to help! If one of us doesn't have the answer another, or 10, will...
As mentioned above, cut carefully and keep to your 1/4" seams and that will help a lot. Some people even cut a little big and trim down.
As a first step, my advice is to get a good board and rotary cutter and find a video that teaches you how to straighten your material on the grain before cutting. I know Leah Day has a video about it.
Have fun and post a pic of the fabrics you've chosen!
Watson