The only thing I would add (because that was great advice) is to make sure to discuss your expectations up front. A lot of my investors come to me after dealing with an agent that never worked with investors. I have to tell you: being an investor makes you look at properties a lot differently. If this is your goal, you need a like-minded realtor. Otherwise, you may end up doing a lot more work or "teaching" your realtor how to evaluate properties (for flip or rent).
Agents with investor background can also help you navigate through lending options (i.e. conventional versus hard money), should have access to resources to help you (i.e. contractors, inspectors, etc) and should have some access to foreclosure lists, how to bid on HUD and other lower in properties (if you're ok with renovations), etc.
Also, I would highly recommend looking super closely at their comps and ask how they arrived to their numbers. This is extremely important when evaluating a property.
Hope this helps!
Maria