Situational awareness for light aircraft starts by looking out the window. Sounds facile but it is not, because to keep a good look out so you always know what attitude the aircraft is in, have the traffic spotted and know the land features you are seeing....you have to the aircraft in trim, navigation sorted and efficient engine management/checklist use.
When doing checkouts I find the overall competence of the pilot is heavily correlated to the head in vs head out time. Si if you are flying along and realize that it has been a while since you paid attention to what was happening in the windscreen that is a clue that you need to reestablish your SA right away.