While rates are a concern for savvy investors, it's important to understand the different ballparks of residential mortgage rates versus investor rates.

Hi Ayyoub Research is the key, Conduct thorough market research to understand why the competing property is listed at a lower rent, Consider any improvements or upgrades that could enhance the appeal of your property to potential tenants, If you're unable to match the lower rental rate of the competing property, consider other incentives to attract tenants, such as offering a shorter lease term, including utilities in the rent, or providing additional amenities.Hope it helps.

By my understanding, they pay a fee to apartments for the background check and application, right?

Keep in mind this has been a "sexy" asset class and most people don't understand or even look at the numbers.  

Would attending a real estate school or taking specific courses be beneficial in understanding the fundamentals?

If you have solid equity in the deal or if you have increased your credit score.

I just didn't understand when I asked the lender if she could price the interest rate at a lower purchase price and she did and the rate actually went up even more . 

It will give you a better understanding of what is being bid and therefore know if you are getting a good price.  

Also, what this bunch may not understand is that many times you pull your comps before going to the subject property.

Use an agent that understands the investment strategy.