I've been working on amigurumi for about three years now, and I started with WolfDreamer's Mew. It was interesting. My tips:
1) Look up invisible decreasing. It makes your patterns look so much nicer. It generally goes something like this for single crochet - sc2tog: IN FRONT LOOP ONLY insert hook in front loop of 1st stitch, insert hook in front loop of second stitch, yo, draw through two loops on hook, yo, draw through last two loops on hook. Work regular sc in other stitches (aka through front and back loop) until next sc2tog. Repeat.
2) Stuff VERY firmly unless your amigurumi has a great shape on its own. Even though it isn't as squishy and cuddly, it will keep its shape better.
3) Keep your gauge/tension steady. In most amigurumi, unless you are trying to get the exact same size as the pattern, it doesn't matter what your gauge is as long as it is constant.
Feel free to message me if you have more questions! I'm also on Ravelry as Komekoro