There is one power outlet (double) in my room where the top outlet turns on/off from a wall switch and the bottom one is always on. I just replaced the outlet with the new one, making sure all the wires go into the same holes in the new outlet as they were in the old one, but now the top outlet is always on as well as the bottom one and the switch does nothing to it. This is my first time replacing outlets (learned off youtube :)) and I have no electrical experience (just using common sense) so I can't figure out what might be wrong. Did I need a special electric outlet, or did I somehow mess up the wiring? Where do I start?
Look at the old outlet and see which tabs were broken off on that. You've already figured out the "hot" tab needs to be broken off. Depending on how the house is wired, the "neutral" tab (the side with the white or gray wires) may also need to be broken off. Replicate what had been there before.
There are rules about neutrals (basically: each circuit, i.e. all the stuff powered by one breaker, must use its own neutral, the one bundled with its hot wire - and not "poach" a neutral from another circuit. This is to prevent fires from a neutral being overloaded.) That matters if the switched lighting outlet is fed from a different breaker than the unswitched outlet.
It's a picayune electrical-code thing, but it'll help later if you ever upgrade to GFCI or AFCI breakers. (which is a good idea).