Quote: "do have any suggestions for game programs?"
I am not sure what you mean. If you mean suggestions on what games to try and code for your start in dbp then i'd suggest pong or breakout for starters - they are not as easy as the look although they are quite easy compared to the other genres you can get into later like RPG's and FPS'
Quote: "what would be a good skill to practice? i have heard level design is imortant for developers"
Level design is usually achieved by using an in-house tool that a developer wrote specifically for the game being made by the rest of the team. So level design, as you ask, really is moot but that is not to say you can't focus on one of the existing tools out there like Valve Hammer Editor3.4 for Halflife-type BSP levels. That's a good endeavour. The guys who made Counterstrike just basically made a mod for Halflife, which turned out to be so good that it got picked up and published as a stand-alone game that you can buy retail! Other development is main game coding/game logic. Either you are producing a game engine which handles all the physics internals of the game, or you are coding the rest of the aspects of the game logic -- it's hard to say or suggest what you should do, it depends on what "grabs" you the most. Try making some simple games in dbp and see which aspect has the greater allure for you - that may help you decide which path to take. Remember, people are always here to help with problems, and people here "love" to critique demos of games!
hope I have helped somewhat.
-RUST-