Jonathan Little has written a good series of books on tournament play.
Doug's advice is spot on
"Each tournament situation is influenced by how many big blinds you have and how your table is playing.
Don't freak out if you have less chips than your opponents, for the most part it really only takes a few hands to get back into it late in a tournament.
Knowing how to play a short stack will help you a lot. You can learn a lot by short-stacking in cash games or by practicing in sit-n-go tournaments.
You should have an idea of your opening range from each position at various stack depths (number of big blinds) and be able to adjust these ranges for tight/loose players behind you. There are many players that do not 3-bet without a monster and will fold 80-90% of their big blinds (the easiest raise-fold steal of your life).
Changing gears is going to be important as the blinds go up as well. Usually you will be playing tight, but you can mix in more steals against tight players and re-steal three-bets from loose players... if there are players who will aggressively play back at you, use more value hands.
The deeper you get in a tournament, generally, the remaining players will have a higher skill level. To consistently do well, you will need to differentiate yourself by making plays to pick up chips in spots they would not (or by not losing as many chips as they would).
When you run good and get a big stack you can start to apply pressure and secure your spot at the final table as others hope to hold on and move up the payout ladder. With enough practice you will get better and better at this and should make plenty of final tables if you play a high volume of tournaments.
So I guess my general advice is to study push/fold charts and/or ICM Nash Equilibrium (what percentage of hands you can profitably open-shove off your chip stack given the other stacks at your table and the tournament payouts). Also just playing a lot of tournaments and watching Twitch tournament streamers will help you get experience.
Good luck at tables! "
I would add, learn you opponents' styles and play them accordingly.
You also need to know when to steal pots to maintain your chip stack or you will blind off, very important as discussed by Doug.