For me I use index finger/thumb pressure and then the other fingers are free to move around and fret other notes. In essence the index finger/thumb pressure acts like a temporary capo. Part of moving onto barre chords is getting sufficient strength for the index and thumb to act in that way. There are exercises to strengthen and hopefully help so don't be too disappointed.
Another thing to note is that you don't need to keep the pressure on all the time. eg if you play a barre chord you could play the first beat with pressure, second beat relax, third pressure, fourth relax. That'll give a percussive feel to your playing. And whilst you're doing so your index finger/thumb gets stronger.
I'm a long, long way off from being expert and others may have different, better suggestions.