Mostly I  don’t watch videos about photographic techniques (not because I know everything, but I kind of like to do my own thing and not copy others) but this was a really great video by Kebs Cayabyab that shows 5 ways to separate your subject from the background without using shallow depth of field.   You should watch this 7 minute video!

TL/DR,DW here they are:

1.  Light/Shadow –  Use selective lighting to show your subject to the viewer
2. Colors – Find contrasting colors to make your subject stand out of the background
3. Subframing – Use geometric elements to frame your subject inside the image frame
4. Layering – You should watch this part, but basically using reflections and double images one can create layers of imagery which can isolate the subject
5. Motion Blur – works when you have either moving subject, or moving background