It's not really the game you're in, it's the players you're up against. At 15/30 you'll typically see a lot more people who know what they're doing. . . and who watch what you're doing. At 1/2, you'll find more people who don't know what they're doing, and wouldn't know what to make of you even if they paid attention. So the general strategies can differ. . .
But it's really not because of 15/30 and 1/2. It's because of the players there. If I raise in to a pot and the two players who see the flop with me are smart poker players, I play the rest of the hand "like I'm at 15/30." If the two who see the flop with me are typical loose-passive newbs, I play the rest of the hands "like I'm at 1/2." It doesn't matter what the real stakes are; it matters who the players are.
Preflop, you have to go by the mix of players actually at the table, and that's where absolute strategy differs most between game levels. At the lower stakes I play, I am surprised at the hands with which many people will call an extra two bets after limping -- and shocked by some of the hands with which they will call three bets cold. Because of this, I am very aggressive with pre-flop raising. . . which merely convinces these people that I am full of it, and they go on calling me with inferior hands!