There seems to be a lot of information about what kind of property is better for investing, what methods should be used, what the numbers should be, and the such but I'm having a hard time finding information about what things to look out for when at the property (or looking at pictures on the sites) and what questions should be asked of the agent/owner?

From my newbie eyes, some of the properties I see on zillow, redfin, trulia, etc seem ok? Minor touch ups may be necessary but nothing deal breaking I would think. But I'm pretty sure I'm missing a lot. And if I go to the house I'm sure it'll be clearer but I'm thinking there are other things to look out for?

As for the questions, what are questions I should definitely be asking to make sure everything is in order? Am I allowed to talk to tenants if they're present? Am I allowed to ask for proof that the tenants are paying properly and on time? 

If there's a guide somewhere I'd be grateful if someone could point me in the right direction.

Sorry for the (probably) dumb questions

Thank you