I have a friend that has been trimming her own big horses for a while and while at her house I would just watch what she was doing. I would ask a lot of questions and she would show me anything I wanted to learn. She had some great study cases, a laminatic mare, a yearling that looked to be going club footed, and one that was just hard to get to stand still. Now all her horses have near perfect feet. She gave me confidence to do my filly when I got her home. I also got the Pete Ramey book and here soon will be ordering a DVD set. The biggest thing is to learn all you can and whenever there is an article or a new book out, get it. Follow the hoof and you will never have problems.
As for what equip you need...I have a 14in rasp(I am going to get a shorter one tho, it is hard to use on foal feet), a set of nippers from TSC and a right handed hoof knife and a narrow blade hoof knife. It is better to get good equip to start with then you won't have to keep buying more. I know myself since I have a foal I trim every 3-4 weeks a real good time consuming trim. And in between I will rasp and check the balance and angles of the hooves.
I also frequent other boards that have hoof forums and look at every thread. One board I go to has several farriers that are on it and have several people that have been studying hooves for a long time and really know their stuff. I will say that all of that has helped me be more confident and want to learn more.
Also if you have thrush it is better to use Apple Cider Vineagar than Bleach. Bleach is harsh and kills live tissue as well. It does kill the thrush but it is hard on the hoove and does damage to good tissues as well. I treat with ACV about every 3 days during non thrush times and my filly's hooves are nice and strong. When she came home she had thrush, we had a few days of rain and she likes to stand in the mud and muck. After a few treatments of the ACV it was gone. I use one of the picnic style ketchup bottles to administer it and my friend uses a regular mustard bottle. They just seem to get into the collateral grooves better and help out that much more. Good luck and have fun with trimming. I know I feel much better knowing that I am taking care of her feet and I know exactly what is going on with them.