@Jerrad Dumont Consider cash flow, capitalization rate, cash-on-cash return. I'm not huge on rentals, but when I am using them in the shorter term, I would look at each of those and make an assumption as to the how much on-going costs will be, in terms of insurance, taxes, wear and tear, utilities, vacancy. These will vary property to property, neighborhood to neighborhood, age of the property and certain aspects. Replacing things like a roof and central cooling aren't cheap. I would also not simply look at your current rent numbers, I also look at the market numbers in the case of vacancy.
I also don't look at in terms of just my rental returns. Depending on your neighborhood, things like cap rate can be incredibly high (war zone), or fairly low (luxury properties). Doesn't necessarily mean one is better than the other. For example, in my geography - Miami-Dade, Broward, Palm Beach County in South Florida, areas like Wynwood and Coral Gables have property values substantially higher than any cap rate rental number you could ever look at. Doesn't mean it isn't a great deal now or the foreseable future. In fact, you could treat them as flips, wholesales, etc. If your in this for the long term, and the municipality is pumping serious money into the area you're looking at, you could make a substantial amount of money on appreciation. Look up the Community Redevelopment Associations in you area. A good deal "numbers" in a CRA, in my view, is a great deal when balanced with the real world of a government subsidizing the that area of the city.
This also goes to another point in terms of my recent evaluation of rental strategy. If we're at the top of the market currently, it's not necessarily a "great time" to accumulate a large amount of rentals - I'm not saying don't buy a rental. I'm saying, you think a cap rate of say 10% is great for your market - and your investing in that number. One day, perhaps in the near to semi-near future, you may wish to sell that property. If the market corrects or has a reduction, all of a sudden, you're rental is worth substantially less in terms of re-sale and your for all intents and purposes tied to it.
Anyways, I'm no rental pro - but I'm looking to expand in this area and this is how I am looking at it. If your strategy is simply what every other investor on the planet is looking at and bidding on, going to be tough to find great deals (at least in my market, where people buy things at low cap rates or well over market values). If you can see the bigger picture that other investors aren't necessarily seeing, that's where the "gold is" as general business perspective applicable across all industries.
As an example, I recently purchased a property which may turn out to be nearly a 100% ROI flip. Essentially, there was paying tenant (but paying late alot) in a luxury building with a $1,500 HOA (boat access, crazy amenities) - but with the level of rent it was $1,000 or so loss every month. No landlord was willing to buy it to lose $1,000 per month (and it got floated on wholesale lists like 10x). No regular homeowner was willing to buy to lose $1,000 every month and to possibly move in. Typical flippers weren't going to get involved with a 10-month lease to lose $1k every month. It was in pretty good shape so really I knew I could fix it up for around $25,000 (I did a GC walkthrough with GC specializing in condos). Anyway, I took the risk and negotiated with the tenant post-closing and made it clear that i can pay him $5,000 now to find a new place and cancel his lease, or he can wait till the end and then he will leave. He agreed to the $5,000 - and now I perhaps have the largest flip I've ever done.