Pinning the pieces together works pretty well as does hand basting with needle and thread. Paper clips are, in my experience, more trouble than they are worth. The thing that will help you most, though, is practice. Take some scrap and sew it together again and again until you start getting the results you want. Successful sewing has a learning curve; your first project is likely going to have a few rough edges. Once you can reliably sew a flat-felled seam you are making progress.😀
May I walk in beauty.