Most pattern will tell you what thickness wool to use and hook to attain the correct gauge. there are various yarns available and thier usual names below:
Here are links to some helpful conversion charts you may need!
For seeing at a glance the difference between the american and UK terminology for basic crochet stitches, good to reference when starting out if you are using a pattern in the opposite terminology you are used to.
Above is a link to a crochet hook conversion guide. Some patterns state the crochet hooks needed in each size/gauge but some only mention for eg US K hook, this will tell you the equivalent that you need in whatever hook terminology you use.
This guide from Nerdigurumi will give you a rundown of some of the terminology used in crochet patterns, making it easier to translate them.
Here I'll be putting lists of people/pages etc that have helped me with my journey through crochet. pages with excellent tuition, videos, patterns and more! I'll add to this as I complete works and find people!
Amazing blog from a great crocheter! Laura has tonnes of free patterns, an online shop, excellent youtube tutorials plus so much more!
Sharon over at Amigurumi Freely has amazing youtube tutorials and patterns, and a gret informative facebook page and blog!