Hi Scrubby! You know we just went through this. :) Things I will always look for now: water access! If it's on a well, how much water does the well produce? If it's in town, is there already water and sewer to the house site? Or to the lot line?
Usability of the land/soil composition. Is the land a wetland bog? Solid granite? Sand? Some types of land are not worth building on or can't be built on without blasting or putting in major drainage.
Slope: the flatter the better. Although it's possible to terrace, to use slope to one's advantage, etc, all of that costs money and resources. Flat areas that won't cost a lot to level or where you won't have to build expensive retaining walls are more resource-efficient. Plus easier to grow things on. :)
Consider your preference for trees vs growing spaces. Some people just want to build a cabin in the woods, and in that case the cabin can be built out of the woods. But if, like me, you want to be able to grow things at some point, then access to sun and saving the expense of clearing and stump grinding is something to think about. I love the forest, but we saw properties completely ringed with tall trees and only cleared a little in the middle, and they could be quite claustrophobic once I realized you would only get sun for a few hours a day in the summer and not at all in the winter.. :(
One piece of good news: composting toilets and greywater recycling are being introduced into BC's building code, meaning these should be much easier to get cleared. This potentially means less expense and land needs for septic systems. Yay!
Perhaps biggest: who is the regulatory body that decides what/if you get to build on this property? How easy are they to deal with? What criteria are they using? We considered some of the islands, as you might remember, but realized that trying to get a building permit from Island's Trust might not be worth the wait or the risk...
In permaculture, they consider 1) access; 2) water, and after that, 3) structures.
On another note, you may be buying land with cash and building small, also with cash, which is great. But if not, mortgages for raw land and for building are complicated, and quite differently structured than for houses.
Look into what kind of insurance is available for raw land as well, if that matters to you. Especially if you don't intend to be there regularly.
Last but not least: ZONING! Our search area comprised about 12 different small municipalities (eyeroll), all with slightly different zoning criteria. I spent hours of my life getting to know these. There were vast differences between what is allowed in different places; make sure you know what you are getting into. Realtors often don't understand or care about zoning, but luckily most municipalities have all of the info online. Most require you to find a lot on a map, and then search for zoning by the address or map, and then go through the online bylaws once you know the zoning category. Fun times.
Hope that helps! Happy to share anything I learned over the last year. Sigh.
ETA: Cross-posted with snacky.