I make patterns for people sometimes. Drawing path tiles in AC uses a lot of the same skills as general drawing/painting, and some skills which are unique to pixel artwork. If you want great tips for the latter, look at dedicated pixel art sites. Pixeljoint.com is a good one. They have useful tutorials for all levels in their Resources forum.
Some things I wish people had told me years ago:
* When you want to create shadows, don't use a darker hue of the same color, but choose something with a slightly bluer/purpler shade. Be subtle about it though!
* Never use 100% black or 100% white because it gives you no room for subsequent shadows/highlights. If you want to make something really black use the second darkest shade, then you can still put a bit of 100% black down for shadows. Remember that the game will do some highlighting and shading of its own, particularly for clothes. #
* If you're doing anything with curves or lines that aren't 100% horizontal/vertical, put down some anti-aliasing. Not sure if I can or should embed it but here's a Pixeljoint tutorial that explains it:
http://img155.imageshack.us/img155/4020/aate0.png
