Young Trumpeter

hi everyone. i'm a sophmore in high school and i LOVE jazz. i love to listen and to play and i've got a jazz band concert this upcoming wednesday. only a few months ago did i really start to focus on learning to improvise and with the concert coming up theres one problem that's really bugging me: soft tounging. every time i solo i tend to tounge too hard and it distorts my jazz style and phrasing.

how do you tounge softly? is there a specific spot in the mouth thats better to hit or is it just practice until its muscle memory?

thanks