I've found patience is not especially rewarded in this format. I tried playing very tight as a strategy in both the 15 & 25 minute games, but they are just too fast and there is too much aggression around you for a tight/conservative strategy to work (you have slightly more breathing room in the 25 min). You will usually just fold your way to a tiny stack that is swallowed up when you eventually do shove, unless you get some very strong hands early on. Either that or you scrape through to the money and make less than your buy-in.
An aggressive, but measured, strategy got me into the money more often. If I opened from early or middle I was only doing so with a shove, regardless of effective stack size. I was raising some very strong hands from later positions if I had about 13+ big blinds, but most of what I was opening from late I was also shoving. You'll find no shortage of players willing to call you to stack off, and if they don't you pick up the blinds/ante anyway.
Take more care if someone has opened the pot before you, I was playing/shoving a lot less hands in that case, sticking to premium hands.
In the blinds pay attention to where the opening bet has come from. You can consider a shove over the top with a looser range if the pot was opened in late position.
If you've hit a few big hands all in and built a nice stack you may want to tighten up and protect what you've got to an extent - but you need to balance that with taking advantage of the small stacks when opportunity presents, don't give them a free ride. Do avoid going up against other big stacks unnecessarily.
Remember every chip you hold when the 15 minutes is up is more $$$, so generally you do not want to play for time, you want to play fast and accumulate chips, unless you're down to the last minute or so and want to avoid paying blinds again.
Well gee that sounds easy now doesn't it? Our friend variance will soon bring you back down to earth, it is a pretty brutal format from what I found. Doubtless someone out there has a more +EV strategy than me also, but those are my thoughts.
Bit of info here if you have not found it yourself:
https://www.pokerstarsschool.com/article/Time-Tournament-Tips