Flying geese are sewn on the bias, which can be tricky. Be sure you don't pull or tug on the fabric as you sew it. Let the feed dogs do their job and just guide the fabric. Do you use anything as a seam guide? foot? tape etc. This block has a lot of pieces, so if your seam allowances are off, all your blocks will be, well, unique and may not fit together. This is a challenging block for a beginner, so don't be too hard on yourself. As you stated, with practice you will improve.
this forum has a great tutorial section. There are many ways to construct flying geese, here are some:
http://www.quiltingboard.com/tutoria...s-t180442.html
http://www.quiltingboard.com/tutoria...sy-t20950.html
http://www.quiltingboard.com/tutoria...le-t73445.html