to win a mtt you need all the things come to your side
in a slow mtt with a deepstack maybe you need less but still, you need the sets to be in your side not against, the projects with big pots and incomplete projects to be in the other side as well, also you need to bluff and not to be bluffed, also you should be dealt a lot of playable hands like pockets, aces, broadways suited connectors and quite often you will hit the board and get rewarded with big pots, also you need tables where you take the lead so you can steal the blinds, and so on,
now if you play a lot of tourneys there are a few you will run in that way I describe above, you will lose smaller hands but always your stack will cover your opponent`s so you are not going to be busted and at the end of the day you will be seated in the final table, and it will happen again until you reach the heads up and again until you win it all
unfortunately there is no magic recipe and it not depends totally on you (well yes, depends on your patience to wait for the right moment or the right tourney but you only will realize it when is all happened)
there are moments that you can feel it and then you get that pocket kings and you know it will happen, there are few players left, and this lag player is stealing blinds like crazy and here he comes again, you think for a moment, your kings wait, you think, 3bet? shove? you have the bad feeling, you know you want to win it and the drought, you know you need to stop this lag guy stealing blinds, you dont have too much time to decide, you take a deep breath and shoot... and yes at the end of the day a lot is reduced to luck but that is life and poker is part of it