It's a different mindset -- and different priorities. Clearly, the clock becomes ever more dominant with shorter time controls, and so your priority as a player must be to properly handle the clock. This also means that your style of play and even decisions may be influenced by the clock -- e.g., sharper, less predictable play (if you can handle it) may yield better results against people who don't defend so well, and defending well is always time consuming. Also, you may choose very different moves in a blitz game precisely because with only a few minutes for each player it's less likely that non-obvious mistakes can be caught easily by the opponent.
That's my perspective, but I must say that I am not the best blitz/rapid player, so other strategies and suggestions may indeed be more effective than mine.
Especially rapid?