Any backyard/deck pics you could snap to show where they can relax and enjoy their morning coffee/tea outside?

That's brokering.Wholesalers do the same sort of thing, but use techniques like assigning contracts or double closings so they are a principal to the transaction. 

Need to calm down and relax because wow.

That's not a common situation, so it isn't usual to get owner financing.Certainly its neater if the seller own's it free and clear, but creative techniques like AITD (all inclusive trust deed), lease options, and contract for deed are all ways to do "owner financing" even if the owner has a loan.

I have been reading like a mad man, and I feel like I have a pretty solid understanding of financing, renting, selling, controlling the properties you buy and a variety of other techniques and investment methods (I have not actually done any deals, however - I'm only 18).However, there's still one definite gray area that remains, and that is this: what are the risky  aspects of investing? 

Read everything you can by Grant Cardone for mindset and check out books by Roger Dawson for pure negotiating techniques

You might think of taking a jog outside and, as you relax from the exercise, practice in your mind what you will say when you call these people.  

Relax and be yourself.

In addition to using craigslist or postlets, what other marketing techniques or tips are other people currently using to attract tenants to properties?

It appears to me that the majority of them are just marketing techniques and they are going to produce a killer deal.