Probably the most important consideration is that the helmet fits comfortably. You'll need to try them on for that. Some people have round noggins, others are more square shaped and helmets run the gamut of shapes as well. You want to feel the helmet contacting your head fairly uniformally all around. If it hits just a few spots it will chafe and be a nuisance. Try the helmet on with your googles so that you find a good fit between the two. The goggles may push the helmet up, the helmet might raise the goggles off the face, etc. What this boils down to is buy for fit, not for brand. Then consider features.
Ventilation is pretty common but runs the range from wide open vents, ala bike helmet, to openings with louvers that allow airflow to be adjusted as needed. Many wear a helmet liner hat or not to adjust for variations in temperature.
After considering fit, you'll want to decide if you want hard ear and temple protection (required for USSA and FIS racing, if that matters to you) or a soft side helmet. Most recreational skiers will get the right balance of protection vs. comfort by using a soft side helmet.
I've used GoPro's helmet band to attach a helmet with excellent results on a full cover race helmet. The open vent style helmets are accommodated easily with a 'through the vents' attachment. Otherwise any smooth surface on the helmet will do for the sticky tape attachment.
How you wear your helmet is important as well. Too many people appear to think a proper fit is tilted back (more prevalent with soft side and 'shorty' helmets) which is not correct. The helmet is designed to sit with the front edge slightly above your brow. This protects your forehead. Whatever you wear under your helmet should not cause it to be rasied off your head. You want to feel it snugly on your head. A loose helmet is going to jiggle around and afford much less protection than a properly fit helmet.