What to look for when buying a used Hybrid car (WagonR/Aqua/Fit)

I’m planning to buy a used hybrid car (WagonR/Aqua/Fit preferred). It will be going to be my first car and I would like to have your suggestions on what I should look for.

Also, do I need to bring a mechanic to inspect the vehicle? If so, what are the things I should look for in that mechanic person and how can I find a good one?