To find consoles or people to talk to, I have to approach them and see if I get the circle that lets me know I can interact with the object.
Is there a better way than running alongside all the walls in every room, to see if I can interact with consoles? Are the interactive ones different than the others? Can I "look" at them and have a tooltip tell me they're interactive?
No, not that I've found. The only indication is the circle you get when you're getting close to one.
I tend to run around the outside of every room, and along side every potentially interactive object in order to avoid missing any of the bits and bobs and stashed items.
The only downside to this is that in cases where you're continuously threatened with more enemies, or if you've got another reason to be time-limited, you're going to have to work fast lest you fail the mission or miss something important.
There wasn't a way to do that in the previous two games in the series, and as far as I know there isn't one in Mass Effect 3. Running around and waiting for the circle to appear seems to be the only way.
If you're looking for Quest NPCs / interactable objects, you do have one method of recourse - quest pertinent interactions show up on the Map (m), though this only works on the Citadel and the Normandy.
The map unfortunately doesn't do a perfect job of showing where each item is, but it should at least give you a way to refine your search to a smaller area.
