How do you trim an Angel Trumpet/ Wedding Bell tree?

I have two in my yard, a yellow one, and a pink one. the pink one is rather large, but lanky scraggly and thin. the pink one is super tiny and scraggly. My grandmother died and then my yard went through six years of no watering trimming or care. I started overhauling the yard recently. The pink one was mainly dead wood. and now consists of one 6 foot tall trunk with maybe 2 leaves. The yellow one is mainly alive and I was wondering how to trim it properly so that it blooms thick and full.