I've been a member and listening to all the podcasts for 10 months or so and fear of what I don't know has hindered me from taking any action.

Congrats on taking action and working towards your financial independence!

The fact that you took action is a great thingYou have to decide what you want to do.  

As an extreme action, I told him I would let him out of his lease if he felt this was unlivable for him.

Con: They reduce my monthly cash flow (6 - 10%)Manage it myself:Pro: My cash flow is increased (at expense of time)Pro: Online tools make it easier for me to remotely manageCon: Time-consuming, especially during the leasing processHow to find a good property manager / leasing agentI go online and get reviews and quotes (Yelp, Thumbtack)I ask for 3 referrals or reach out to those people (note: I also ask tenants, since I want to make sure my tenants are happy and treated well)I ask what online tools and processes they use (for example, if they don't have an option to collect rent online ... then they seem pretty inefficient to me) I ask about transparency -- will they provide me with the background check, lease agreements, etc.?

The best advice I can give you on that aspect is to use your current situation as motivation, rather than let it consume you.  

I've been reading BiggerPockets for a little while now, and I want to start taking action.

Such an actionable book.  

Get a company do your direct mail.Option 1 will be the cheapest and most time consuming.

It sounds like you are an action person so take action, BUT make sure you do your Due Diligence on the property.