John, here are few thoughts that come to mind:
1. The realtor. Look for one with extensive experience in the multifamily market. One who lives and breathes multifamily, one who understand the local market, the general CAP rate for each area of the Dallas market, the crime rate, the demographics, etc. Residential realtors seldom have this knowledge as they are too busy with SFR's.
2. The property. You may want to look for a smaller property in good condition, with no deferred maintenance or major structural problems, in a good location. I say this because I believe you may be an investor with limited experience in the MF sector. If that's the case, you don't need headaches with your first MF property. While owning your first property you'll learn whether the property management company is good enough to handle the day to day tasks of managing. If you're not satisfied with how they work you can explore others (and I'm sure there are plenty in such a big city). That is why you don't need additional projects with your first property such as remodeling and other responsibilities.
Even if you have more extensive experience in the MF sector, with you living in another state - unless you already have and trust the "boots on the ground" to satisfactorily do the renovations - I still think that the type, condition, and location still apply for your first property in Texas.
3. Location. I often see potential buyers get very enthusiastic when seeing high Cap Rates, High ROI's, high Projections, etc. Please keep your feet on the ground and the head on you shoulders. Don't allow emotions to take over. Areas that typically have very high Cap rates are often areas with poor economic features, such as higher unemployment, lower absorption rates, and possibly higher crime. Dallas is a huge metropolitan city so I'd explore areas with good local economic features.
4. Back to the realtor. He/she will have the experience to know which area of the city to direct you to. Thus you may want to ask him/her about the areas where the MF absorption rates are higher. This will be very important to you, b/c your need is to maintain a high occupancy level, with good quality tenants who pay the rent (on time), and less turnover (management companies charge additional fees to rent a new apartment, this means less income to you when you experience high turnover).
When he/she presents you with the areas, you may want to ask how do the absorption rates compare to those of other areas. As questions about the local economy and what makes the area look good for the future. Overall Texas is a great state but it doesn't mean every single county is ideal for investing purposes.
5. Property management. A good CRE realtor should be able to recommend a few companies. If not, do a search. Regardless of how you get their names you should be able to review their websites. Only after looking at the website I'd call and interview the few that I'm impressed with. I wouldn't settle for a company that manages SFR's. Again, you'd want to have a company who strictly focuses on the kind of property you're looking to buy. One that is experienced with the local market and has been in business for a while. When reviewing a property management company, keep an eye for those that also have the ability to act as asset managers. What I mean by that, some of these companies have the ability to help with projections and calculations to increase a building's cash flow, also have "boots on the ground" to do renovations which may be associated with future properties you may purchase in the area.
I'd say this is a good start. And since you're doing a 1031 time is of the essence.