A lot of luck, pick your spots..
To make it happen in freebies, you need to take chances, think of freebies as a one-off, tourney. You need to shift your focus from your normal game, become aggressive, wait for opportunity to pounce and get your stack going, especially if you are a timid, tight player.
Luck is essential. Luck, as the game plays out, not being dealt "lucky cards."
Another thing is to realize how you must keep the blinds in mind, be aware.
Often, a player kills it in the start of the tourney, relaxes, with a "big" stack, then realizes the blinds are up, everybody has as much or bigger stack than me.
Keep an eye on the average stack and the big blind, you always want the stack to be at least 10x the big blind. Often, it forces you to be aggressive. But that is what it takes to get ITM, I'm not going to give "winning advice", never won one yet.
Be ready to make aggressive moves, but not just with AA KK other monster pairs. My AA lost to KJ when Q109 came up on the board. Suited connectors are favorites for me.
Also take this with the advice of other members.