I've been going through Royal Road to Card Magic for about 8 months so here's my tips overall in your endeavor to learn card magic.
1. Buy only bicycle cards decks. No sense spending loads of cash on decks that will quickly get worn out just practicing the basics. If you want to splurge, get some nice Tally-Ho's. When I get better (I realize that's subjective) I may get something nicer, but to be honest, people may suspect something fishy outside of Tally-Ho's, Bees, and Bicycles.
2. Definitely like the others above recommend the Royal Road to Card Magic. Of KEY importance is NOT to advance to the next chapter until you REALLY can do the slights etc. listed. I'm still stuck on p***ing after two months. I did purchase the DVD companion to this from Paul R Wilson but I read AND watch. Love the DVD.
3. I would re-iterate the value of FOCUS. There is a GLUT of information and materials all over the place. IGNORE it all and focus on the ONE book and getting better.
4. When practicing a slight, do it for a while very very slowly while watching yourself and making sure it's done right. Long sessions doing a slight incorrectly only prevents further advancement. When you're better and know it's done right, then start doing the slight without looking at your hands. Then don't look at your hands and check yourself in a mirror. Then don't look and rehearse your patter (as your shuffling etc.).
5. I would encourage to practice short amounts every day vs. a long time away, then hours at a time. It's like meals, don't gorge yourself and then starve yourself.
6. There's a great free theory book from Vanishing Inc called "Magic in Mind". Practicing slights is one thing (important), but understanding magic theory and performance art....equally important. You don't want to become just a guy who does trick after trick after trick etc. This book is a great smattering of information from loads of great card magicians. Did I mention it's FREE?
7. Put a budget for yourself each year. For myself, all in, I will spend no more than $100 a year on magic stuff. That includes cards, DVDs, books, etc. It makes you a lot choosier, a lot more careful to think through what you really want your card magic to become. I end up buying One book, one theory book, and a brick of cards. After that, it's just practice and thinking through what effects you want to learn and what type of magician do you want to become.
8. To be well rounded, listen to things like the Scott Wells' Podcast and The Magic News Wire, I've personally learned tons about magic and thinking behind magic by some really amazing magicians. Don't re-create the wheel, learn from those who have come before us.
9. Find trusted folks that you value their constructive criticism. Don't just take ANYONE's Criticism. Understand WHO is giving you feedback and are they qualified to give it. You want folks who know their stuff and have an interest in you improving the art.
10. My own take on youtube is to just focus on performances and only from those artists who have highly stood the test of time or highly regarded in the magic community. Youtube does have loads of stuff, so be very very careful. Even if you don't like certain great magicians like say, a Darwin Ortiz, you can still learn something about performance, and can at least start to see what STYLE of magic you like.
Hope this in some small measure helps you along your exciting pathway. I'm loving learning card magic and hope you do to!