First, narrow down purpose (carry vs. home defense). Next caliber and capacity (small, medium, large). And budget (low, medium, high). And finally whether you want a semi-auto or revolver, and if semi-auto, whether you want steel vs. plastic, and external or integral, hammer vs. striker, etc..
Then, by asking advice on brands, makes and models given criteria, a newbie would have probably a handful of guns to go fondle and perhaps rent/shoot.
When looking at guns, manipulate the controls (can you reach the trigger in DA, can you operate the safety effectively, can you action the slide properly, etc.). How does it fit, balance, and point for you....? Too fat, to thin, etc? Do you like the trigger (always ask first if you can dry fire a weapon before you do)? Does it speak to you? Is it comfortable in the hand (keep in mind that you will add several oz of weight to the rear when it is loaded, so some polymer guns may feel front heavy but actually balance quite well when loaded).