I'm sure there are a vast number of ways to do this. I'll be looking forward to some of the user responses to see what others do!!
I personally export a .svg from Figtree and edit it using Adobe illustrator. I like this because it allows editing of all aspects of the tree: tip names, branches, etc. You could probably also export a .jpg or other format and edit in photoshop or other imaging editing software. I know some folks that prep in powerpoint. Illustrator has a bit of a learning curve, and it can be costly ($). I use it because I primarily becuase I already have it for taxonomic illustrations.