@Logan Beckner Depending on your market, it may be best to furnish the rooms. This will also help for photographing the room for your advertisements. I rent out 3 bedrooms in my house and have found the rooms much easier to rent once I furnished them (basically 0% vacancy). You don't need to go crazy. I bought nothing new - all used furniture that was either in good condition or had the ability to look nice with some elbow grease and paint. Mattresses are another story - I was lucky that my parents live close by and they were looking to get new mattresses, so I took the old ones off their hands. I also bought another used one, but make sure you ask the seller about bed bugs, etc, and when you go pick it up, take note of the condition of the house (nicer house generally means the mattress was well taken care of).
Nice furnishings for common areas - again, no need to go crazy with expensive new furniture (unless that's what you want). Recommend TV for living room, as it's not feasible to have them in every bedroom (unless tenant provides their own). My roommates don't use the TV, they either brought their own or use a tablet/laptop. I provide all of the kitchen amenities, including things like trash bags, paper towels, etc. However, tenants are responsible for their own toilet paper, toiletries, etc.
Make sure you have enough parking spaces! This is something that is very easily overlooked. Since this is a townhouse, I'm thinking you may not have much (if any) street parking. Probably a 1-2 car driveway. Is there an extra parking lot in the complex that your tenants will be allowed to use?
Also make sure that amenities that you advertise can indeed be used. For instance, if your complex has a pool, can the tenants actually use the pool or is it strictly the homeowner?
As far as screening, this is really an art form. Experience is the best teacher. Create a list of questions that you want to ask your potential tenants. Ask basic screenings questions during the inquiry stage - what kind of job do they have, what's their work schedule like, etc. Those questions should be made to weed an undesirables out. Then you can have a separate list of questions to ask when showing the house/room. These should be questions like, do they have guests over often, do they have a significant other that will be there a lot, how long do they plan on renting... you'll come up with your own that are tailored to your needs. I prefer people that are single so I don't have someone else in the house all the time. And the parking situation as well.
I try to find people with similar professions and work hours around the same age. Since this is an "intimate" living situation, you can legally ask about their age and screen based on that. You cannot advertise anything with a discriminatory angle, but when you screen you're allowed to rule out.
You'll get the hang of it. We all get "duds" sometimes. Even the best roommate can turn into an a-hole. And sometimes those that look good on paper and interview well, end up being inconsiderate and rude (ask me how I know...). Stick to your guns - if someone is violating the lease terms (i.e. always loud during quiet hours), confront and if they keep doing it, give them notice to vacate. Be nice but don't put up with anyone's crap. I'd rather lose out on a month's rent than get a crappy roommate.
Good luck!