Layout is very important to me. I hated the last Gigabyte ITX board I got. It had the 4 pin CPU connector somewhere on the middle of the board, HD audio placed far apart from the rest of the front panel connectors, USB 3.0 similarly inconveniently placed, capacitors very close to the CPU socket preventing certain cooler orientations, etc. I built with it in a number of cases and it never came out clean.
Fan header count/placement and fan control is also important to me. I don't want to have to use splitters to use as many fans as I want to install. PWM fan control would be nice too. I'm not going to use a separate fan controller or inline resistor. That makes the cabling uglier.
Also I want a M.2 slot on my next board so that I can have internal storage without SATA power and data cables.
I care so much about orderly cabling but the color scheme and coordination doesn't bother me at all. Not sure why. I'm not color blind. I would happily buy a classic green PCB motherboard if it did everything I wanted.
No one considers the quality of the BIOS? I have been looking for a new mobo and basically looking to go Asus because the z97 BIOS looks very practical.
I still consider Value a major component of decision making. I got my i7 4790k and Gigabyte z97 Gaming 7 board bundled together for $400. Had I bought the CPU and Motherboard separately, I probably would have gone with a different board for aesthetic reasons but I also would have been spending an additional $100+.
Application.....where is it being used, for what purpose, and by whom.
Desired CPU based on #1
Feature set needed dictated by #1 & #2 (this can be anything from chip-set to the number of SATA ports, or integrated GPU..etc)
Manufacturer... I don't want headaches from buying junk and trying to make it work.
Seller... where am I going to buy it, not everyone sells everything. this has a lot to do with how a company deals with warranty issues and RMAs because it's gonna' happen.
Price ( a saving of $10 or even $20 isn't necessarily a deal if the company is a pain in the ass and has issues dealing with returns, warranty, or RMAs) (sometimes how the company is to deal with if you get a DOA part makes them worth a paying premium because you know they have your back and there will be no hassle to return goods)
Aesthetics...while it's not important if the color match, but if it is a option then it is a consideration, but not a big deal I'll mix red ram in a blue motherboard because I'm buying a spec first then price not a color, color is actually my last consideration if I consider it at all. I don't build a computer to put it on display it's built to perform a given task. When the build is finished I'm not going to pull it out and take the cover off so people can go ahhh you matched all the colors that's so cool...who cares....but I do like a nicely laid out case with good cable management and a clean look but more for air flow and trouble shooting than to impress anybody.
Sort by socket and then verify compatibility with my selected CPU
Find one in my price range
Pick one the correct size (ie ATX)
Pick something that has the right amount of USB headers, PCI-e lanes, ram slots, fan headers, etc. for my usage
Look at the power phases and see if there are enough (and research the quality of them) for overclocking
Finally, research if there are any issues with the board as well as check reviews and ratings
Seems like a long process and sometimes it is but the motherboard is important and can cause big headaches later on if you get one that doesn't fit your needs, has quirks, has an incompatibility with certain hardware you're using, etc. so it's worth the extra 30 mins or so.