Aye, First and foremost it needs to fit your face.
Without using the strap, place the mask on your face and inhale slightly or hold your breath and press in on the mask to create a vacuum. Take your hand away. The mask should stay put. If it leaks air doing this, it will leak water.
The mask needs to be made of tempered glass. This should be a no-brainer, but given the state of manufacturing in today's world I'd be careful with off brands.
If you're in a dive or aquatic sports store keep an eye out for these. I don't know who manufacturers them but they show up regularly as generics at less than a third the price of the name brands. Masks | Halcyon Dive Systems
Several of my co-workers use them and have been really pleased with them. As a bonus the black skirt prevents the annoying reflections you can get with clear silicone skirts when the sun behind you.
In addition to getting a mask that fits properly, if you wear glasses or contacts, get a mask that can accept corrective lenses. It really makes a world of difference, even if your prescription isn't terribly strong. The best bet is to go to a good dive shop and talk with the folks there.
For some folks the $5 set at Walmart will keep them happy. For better rubber or silicone, you can easily spend $50 and in order to check the fit, you really need to go to a dive shop or other store that has literally several dozen on display that you can try out.
Once you've used a mask that really fits well--you'll appreciate the difference. Or, you can just buy a cheap one and keep blowing the water out as it trickles in. If you're just going to use it occasionally and at the surface, that may be good enough.
Some actually have a little flap valve under the nose, so you can "blow" water out without having to lift the edge of the mask. Might or might not matter to you.