They returned my initial call nearly instantly, asked me what I was looking for, and tailored suggestions to my requests.  

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

I'll be happy to address specific questions, I can tell if someone has searched and has made an attempt to learn or if they simply feel entitled to be spoon fed information tailored just for them.....without regard for those who contribute because they just don't want to look anything up.

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.

He'll probably know how to BRRRR or at least buy/hold techniques. 

The difference between a three-year thinset tile job, with three years before the tiles start to crack and pop off, and a seventy-year thinset tile job is just a matter of good technique.3.

Another technique that a value add syndicator will do is renovate a few or say 25% to 50% of the apt community to show the potential buyer a proven strategy of what renovations can do.