Here goes...
1. You need to realise that, as with all extreme sports, you wont get anywhere unless you're confident. To be more specific, when attempting a trick, you have to KNOW you're going to do it and make it, you can't hesitate. The more you hesitate, the higher the chance of you falling over. You have to be sure that you are going to nail the trick 100%, if not, then theres little chance of you doing it.
2. Falling doesnt hurt 90% of the time. It might sting a bit, but on the VAST MAJORITY of falls, you will be able to get right back up again and carry on riding.
3. If you do fall, roll on the ground over and over till you loose momentun and stop. It hurts less that way. Often, I fall off my board and fly through the air, but if I manage to roll as soon as I hit the ground, I can get right back up and carry on riding.
4. Wear pads and a helmet if you want. There is NOTHING WRONG with this, and people don't laugh at you. If you really want, wear the pads under your jeans and hoodie, so people don't actually know theyre there

Above all, enjoy it and don't be afraid!