Here is what I generally recommend:
1. The type(s) of use will largely determine what general style of holster will meet your needs. What works best for range or field use may not be best for discreet concealed carry.
2. Everything in holster design involves compromises among the 4 basic factors of comfort, accessibility, security, and concealability. Whenever one factor is emphasized there will be compromises in the other factors. There is no such thing as the "perfect holster" for every user or circumstances, and only the individual user can determine which factors are most important and how much compromise of the other factors is acceptable.
3. The belt is the foundation on which a carry rig is built. Unless the belt is solid enough to support the weight and anchor the holstered handgun firmly in position it is unlikely that any holster will perform to its full potential. I have observed many people disappointed in a holster when, in fact, the underlying problem was lack of a sturdy purpose-built belt.
4. Your usual activities should be considered prior to selecting a holster. Those who regularly engage in strenuous physical activities may require increased security features to properly retain the handgun. Those who spend a great deal of time seated or driving may benefit from different holster designs than others. Those who regularly enter locations where firearms are prohibited or inadvisable may wish to have a quick and easy means for putting the holstered handgun on and taking it off.
5. Your usual wardrobe should be considered. Suits and sport coats provide better means for concealing a carry rig than shorts and T-shirts. Loose-fitting outer garments are generally better for concealment than closely-fitted clothing. Materials having some body (poplin, leather, denim, etc) are generally better for concealment than soft knitted fabrics that tend to cling and conform around objects.
6. Your physical condition can be a factor. Those with range of motion issues in the hand, wrist, elbow, or shoulder will have different requirements than people with greater mobility and flexibility.
7. Try not to be too greatly influenced by the "expert opinions" of others. Examples:
a. Many public and private ranges require covered trigger guards on holsters. This might be a good thing with many of the modern striker-fired semi-autos without external safety devices, but such requirements are primarily restrictions placed by insurance carriers based upon accidents and unintentional discharges that seem to have become more commonplace since those types of handguns came into common use.
b. Many instructors (and writers on this subject) insist that a holster allow for easy one-handed reholstering. This can be very important in law enforcement applications where issues of force escalation and deescalation are serious considerations. But for the typical civilian carrying a handgun for personal defense the reholstering of the handgun is just about the last possible consideration (either you survive the situation and turn your handgun over to the investigating officer, or you don't survive the situation and someone else takes your handgun away).
I could probably go on for hours, but I think the above points should help you move in the direction you need to take.
Best regards.
