remember its all about you, who cares if you wipe as long as you top the charts
The thought scares the hell out of me. This isn't some 5-man where one could wipe and the attitude would be "Meh, we can try again". As a person who started as DPS, I've seen the things that have been said in LFR after a loused up fight. I want to be a raid healer someday, and a good one.
First, practicing in the older LFRs can be good. It gives you a chance to get used to your set up, and chances are, there will be an overgeared healer or two that will cover for any mistakes you might make. Also, you will have 5 other healers there to cover for you. It's not quite as much pressure as being a tank, where if you goof, everyone knows it. If you make a mistake, brush it off - it's no big deal.
If something is confusing, or you need some feedback, the forums (both healer and class forums) are a great resource. We are always happy to help people here =)
If you're looking for helpful blogs, try:
Dayani at Healiocentric does an amazing job at keeping her info up to date. She also provides a general healing perspective in addition to advice for specific specs, so you can really get a feel for how other healers might react to certain boss fights.
Once you learn your spells and passives and set up your UI, it is just practice, practice, practice! If you can find someone to heal with to take you under their wing, then that is invaluable.
Feel free to msg me in game if you ever need some pally advice. My btag is Ffraid#1470 . Good luck!