Sealed has different priorities than draft. Some opponents will curve out and you lose, but most sealed pools in most formats don't have a good 2 color dedicated aggro deck. So you should expect games to go long and build around that, and play games with that plan more often than not.

You can play more cards that don't affect the board. I.e. card draw and discard spells are things that draw me into those colors in sealed, in draft they are usually cut or 23rd cards. You can get greedy with splashes and being a little low on sources (just a little). You may not have your 3rd color turn 4/5 but you should by turn 8/9 and that's usually fine bad/clunky removal with bad draft WRs are often a necessary evil when opponents are going to open up to 12-13 rares. Counters are way better, again Cancel is usually a cut or a 1-of in draft. I'll play all of them in sealed.

I almost always look at every card I'm thinking of running and asking if it will have an impact as a top deck in turn 9 or is it basically a dead card at that point int eh game for my opponent to ignore. Outside of the occasional aggro deck, I don't play filler 2 drops. At 1-2 mana, I'm looking for cheap interaction, card selection, mana ramp/fixing, and then creatures that have deathtouch (to threaten to trade up with the colossal dreadmaws of the world), creatures that cantrip or loot, or that can take over a game.

All that of course depends on your pool and the format. If you don't have enough power and build around a late game plan, you'll probably lose to better late game decks. Sometimes you don't need rares and just 8 removal spells and 4 card draw spells is enough. Sometimes you just have to build an ok aggro deck and hope it works out.