Lately I've been working on some crochet bowls, it took a while to get the hang of it so I practiced some different shapes and sizes. The best thing about crochet being that if you go wrong, you can just unravel and start again!
I've been using Tektek tshirt yarn, which is made in Portugal, leftover from garment production. Each different roll of yarn varies in thickness and texture, so if you want to make a few matching things it is best to get a large roll so that you'll have a big quantity that'll be consistent. I found this tutorial from The Makery really useful in getting started. You can buy the yarn from there or else from eBay.