Lesson Tips
So, you know what gear you need to have, so now its time to get lessons. I am not going to attempt to tell you what you need to know to start snowboarding on your own, as I believe that lessons are key for getting a good start and should be considered mandatory. However, I will give you some tips on how to make the best of your lessons, as well as tips on how to improve after you are down taking lessons.
Finding Lessons
Snowboarding lessons are offered at pretty much any ski resort. There are many types of lessons available, including group and private lessons, adult and childrens lesson, and lessons for those who are more advanced. Just ask the person at the lessons office what options are available. Lessons are typically offered in full and half day formats. A half day lesson gets you instruction up until lunchtime, after which you are turned loose to fend for yourself on the slopes. A full day lesson lasts for almost the whole day (usually until 3 p.m. or so), and gets you the most instruction possibly. Obviously, you will learn more from a full day lesson, but if you cannot afford it, a half day lesson is much better than no lesson at all.
During the Lesson
The biggest key to success during lessons is patience. Like any new skill, learning to snowboard can be very frustrating at the beginning. You will feel quite awkward with your feet strapped together on a slippery board, trying to go where you want. You will have many embarrassing (and occasionally painful) falls. Hang in there. No matter how bad you feel, take comfort in the fact that there is probably someone else in the lesson who is doing worse than you are. 
Patience is key to learning, you will get better with more practice no matter how terrible you feel at first.
Listen closely to your instructor. Though the steps they take you through may seem trivially small at first, they are designed to get you the base skills you need to advance. Take each task, try your best to master it, and build your skills slowly. Also, if something does not seem clear, definitely ask a question. On the other hand, do realize that you are not the only person in the lesson, and that you can’t be hounding the instructor constantly whenever you fall. Save your questions for things that you truly don’t know, and keep practicing the rest.
After the Lesson
After the lesson, you will be given a few words of advice, and then turned loose on the slopes. By the end of the lesson, you should have started “linking turns,” that is, switching from your toeside to heelside edge, and vice versa. This is the basic turn you need to master, and probably the hardest thing to do as a beginner. What will happen until you get better is that you will wind up digging your downhill edge in by mistake, and flipping yourself over, hard. This is known as “catching an edge,” and you will become intimately familiar with it during the next few days of riding. When this happens, shake yourself off, and keep trying, with the full knowledge that you will be improving. Also, when you fall, be sure to tuck and roll rather than reach out with your hands, as this will prevent injuries to your arms and wrists.
When you are first starting out on the slopes, try to stick with the green (beginners) runs at first. However, since many beginners runs are quite flat, and you have no other means than gravity of propelling yourself, you need to avoid spots where you will stall out. The best slopes are ones that have a relatively constant grade all the way to the bottom. Ask your instructor at the end of the lesson where you can find such a slope. When you find a good one, keep doing laps on it until you feel like you can take on more challenging runs.
Once you have the basic fundementals down, turning to friends for more advice or taking more lessons can be a good idea to improve. Watch other riders around you, and see what they are doing. If it seems like a good idea, give it a try and see how it works for you. There is no set style in snowboarding, so find what works for you, and enjoy.