You need to practice a lot. I've been making plushies for nearly 2 years now the first one I made looks nothing like the ones I make now! Try using fleece fabric. Every time you make one, think what you need to change or do to make it better next time.
My pattern is pretty simple, you can buy a pattern from theres lots of instructions with the pattern to help you but you will need a bit of sewing knowhow. I bought a pattern a while back but haven't had time to try it out yet. If you do buy a pattern, use fleece to make it before you use the more expensive minky.