1) I would pick a market I know/understand well. There is no replacement for being able to eyeball a map and know what areas mean what. Maybe there is another market you have a good understanding of?
2)BRRRR offers a lot of attractive options. Will usually come with a lower purchase price and will allow you to unlock equity you can use should you wish to scale faster.
3) Echoing above advice, I think BRRRR is a great strategy and multi-family properties provide a perfect place to employ it. I know SFRs seem like a simpler place to start, but to me, there are a lot of risks with SFRs that disappear with multi-family. Economies of scale ftw.
4) Ask incisive questions. Gauge how much experience they have working with investors. Ask them what pitfalls are most common. If you ask a consistent set of questions, you will be able to quickly tell who is legit.
Also, consider checking LoopNet (for multifamily) and/or REMAX or similar (for single family). If you look at a decent number of listings and see the same names reflected over and over, those agents might be a good place to start. In the multifamily context, those listings will generally be people who are well-versed in dealing with investors.