What do people use to guide their miniatures buying activities? By that I mean beyond, "I want figures for the "third potato diggers war" (historical,) "I want <insert race or species here>" for Fantasy, or "I want telepathic, fast move, light armor, medium weapon, light saber wielding" forces for Science Fiction.
Unlike the last question let me start first with my guidelines/checklist approach.
1) At my stage of life it has to be of a size to be storage friendly. For large mass battles that means 3 mm or 6 mm; for small battles or large 'skirmish' game I can accept 15 mm; and for smaller skirmishes using limited numbers of figures I
will use 25+ mm figures if they are unique and only available in that size. An example of the last is the Soldados de Cuera and Presidials I currently use for 1680 - 1810 New Spain games.
2) With my total lack of painting skills I look first to figures I can field without a lot of details needed (it is easier to paint smaller figures (if you paint them appropriate to the size) because less details really are necessary. IIRC Peter Berry once said he doesn't as a rule paint belts for his 6 mm figures in the middle of a mass formation.) I want to paint the details that matter at table top viewing distances (not museum diorama level.) So if there are excessive details that will be seen "at distance" I am less likely to buy the figures.
3) While I am not a size fanatic, since there is variation in height and build in people, (one college roommate was around 6' 5" plus and 140'ish pounds while I was 5' 5" (rounding up that last 1/4",) and around 8 pounds heavier, I do want some realistic size relationships. For example, if 5 mm = 1 foot and I arbitrarily set human "average height" at around 6' (30 mm) to the top of the head for this example, then I want Dwarf figures somewhere around 20 - 23, maybe 25 mm tall to the top of the head with elves (which I see smaller, faster, and deadlier than humans,) around 25 mm to 28 mm to the top of the head. Dwarfs as tall or taller than humans jars my game mood. See number 4 below.
4) For Fantasy I want Humans, Elves, Dwarf, and whatever other races are in the game to have different fashion styles of apparel, different styles of weaponry, and other details that help identify the figures such as gnomes with some version of the peaked garden gnome hat for an extreme example easily. For Science Fiction I want figures appropriate for the setting (in a toxic or exotic environment figures should have helmets, masks, rebreathers, "something" to keep them alive.) For historical games the figures (even civilian "window dressing" figures) should wear era appropriate clothing. No Togas (except for Frat parties) in a 1930s city bank robbery setting... an extreme example but I shouldn't be able to pick 2014 era Lois Lane out in a 1950s game and I shouldn't have 1930 newsboys in an 1880 western bank robbery game. And while I am fashion challenged, I have experienced that style of visual disruption in the past.
5) Weapons that are practical (unless ceremonial) to the figure. Yes, dwarf figures are "stronger than humans" but two Axes that dwarf the Dwarf in size (pun intended) individually just looks... let me be nice...
bizarre at best. And practical mixes for the genre/era please. If historically there was one BAR per squad please don't put 3 in (or none) a squad sized pack.
6) See above, if you must use blisters/packs (and I understand you might have to do that to remain profitable,) please use some historical sense (research or ask an expert) and make the packs maximally useful in the mix (or sell specialist weapons in packs or single figures at a higher price for your costs.) There wasn't a flamethrower in each squad in WW2 for example so don't provide me weapons packs where there is one Flamethrower to each Light Machine gun okay? Yes that was an extreme example and probably never happened but some of the Heavy/support/specialist weapons packs out there are wasteful in the mix of figures. There are no flag holders for Spanish troops in the SAW so don't provide them OG, please, converting them is a cast iron bitch because of the pose.
7) Are the prices affordable for what I want? Very individual and personal call but if same approximate quality figures cost twice as much or the postage is
significantly more than what your national postal service charges or (for those who suffer this, which I don't,) I am going to get clobbered with "Import Fees" or the like expect me to either A) order less figures or B) use the other source.
Unless you are a single source for a unique set of figures that no one else has expect me to think a long time about ordering. I am going to wonder why your figures cost so much. If you think there is a viable reason for that cost then tell me on the website or brochure why - "My figures are cast in 'Perfectium' metal that bends easily to be positioned where you want the arm/leg/head then holds that position strongly without breaking when dropped from 4 feet above a concrete floor" would be a great reason; My work is worth it," might carry less weight (see same approximate quality comment above.)

Minor but fatal point, don't price your figures so that "more powerful figures"in as game costs multiple times more than a same army, same amount of metal, grunt. You know the companies of which I speak to paraphrase a movie character. Edit - oh my that is the same characters as one of the smileys above.
9) Strictly a personal style preference. Anatomically reasonable sculpts, no female adults with breasts the size of truck tires. And male nudes should not all look like porn stars between the hips and the knees. Children should look like children not dwarf tarts. Nudity where appropriate to be sure but not every dungeon female adventurer looks like a bimbo or streetwalker.
Make them all you want but expect me to
buy them in limited amounts. I am not saying I won't buy
any of them (I have a alternate lifestyle female couple for a particular RPG adventure for what the players "see" in the verbal report from an NPC and a different pair (female vampire and victim) in what they see when they encounter the "couple" in the game, and I had a slave market scene for another game - finding male nudes/partially dressed figures was harder than female one for some reason

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) I just don't need or want them all significantly partially undressed for most games, especially those set before the 1960s.
Okay, there are my major and minor parameters I use when deciding to buy miniatures/figures.
What are yours?
Gracias,
Glenn