Amazon.com link for Dress Your Dog by Sys Fredens
There is a ribbed wraparound vest that would be perfect for a beginner because there is very little shaping or fitting needed. Also, a knit shrug which has simple shaping and little seaming. Although these are mostly knit patterns, there are a few crochet patterns.
There is much more in Dress Your Dog than just sweater patterns for warming up your pooch. Other useful items include also several non-clothing items. There is a crocheted shoulder bag for carrying small dogs and a crocheted collar and leash. There is a knit carry bag, a rug, a striped food mat, a patchwork blanket, two soft pillow-beds.
Dress Your Dog is a fun and practical book with patterns for all skill levels.