sorry, not sure there is much more to say. Make sure they are stable and don't fall over easily and fit size wise. Another thing to look out for is to make sure that they don't vibrate/wobble.
This. Also, even though there was some "padding" on my stands when I bought them, it wasn't nearly enough to stop the monitors from creating resonance in the stands at certain frequencies. Ended up having to also by Auralex foam speaker pads to go with mine to make them usable.
Better stands might be made out of materials that don't resonante as much. Its probably also worth using a level to see if the floor in your studio is level. Turned out mine wasn't and I didn't buy stands with weighted bottoms which makes my stands really unstable. Or if you can splurge for stands with weighted bases just do that.
^ This. I have some of these too and they are fantastic. Not cheap, but the separation is very noticeable in all the A/B'ing I have done. Even if you go the DIY route and just make some cheap wood stands, adding these on top will help. I'd pick them over those isopads that Auralex make any day.
If you're looking for proper stands, depending on your mixing space you could look into making some really quality stands with PVC piping with leadshot in them. Or, buy some
All really depends on how serious you're getting with the acoustics. It does matter how the room sounds and money will have to be spent to make it the best it can be but you can be frugal and get it done if you look into making these things yourself.