They all sound attractive. 

Market the unit widely on popular sites to get a number of applicantsScreen Tenants ThoroughlyCredit CheckCriminal Background CheckSex Offender, Felonies, etc.Check with previous landlord referencesVerify Employment / Assets / IncomeVerify IdentityBe reasonable with:PoliciesHave a fair set of rules at the property and stick with themPricesPrice the unit appropriately in the marketPropertyHave a well maintained propertyI have found that crappy properties attract crappy tenants

In some areas, 2 bdrm units turnover much more quickly, while 3-bdrm units attract longer term residents.

Things like figuring out where markets are in their cycles, what to look for in a specific market to qualify the whole market as being an attractive investment area, and what to look for as warning signs a market may be in decline.  

In my recent listings that attracted flippers one had 4 cash offers one was cash the other 3 where hard money.

At this time, we were able to attract an offer on one of the units, not nearly as high as I would have liked, but still acceptable.

Most of the other groups tend to attract beginners.

I will definitely be in contact soon, what have you found to be the most effective marketing tactic to attract sellers in our area?

They are generally newer builds (usually built within the last 20 years), they come with higher end finishes that attract higher income earning tenants and low vacancy rates.

This attracts a broader variety of potential tenants of which to choose from.