Collect 1000/3000 Blue points
Tech Points are your skill-purchasing currency. They come in 3 different color flavors, Red, Green, and Blue.
Blue tech points are earned from doing many faith/church related activities, or studying faith-related items at the study desk.
First, be aware you won’t be earning blue tech points right off the bat like the red and green ones. In fact, you won’t be able to start earning blue tech points until you are finally able to open up the church, which you need to improve your Graveyard Rating (GR) to 5 first. Once you do that, the Episcop will unlock some tech trees in your skill trees, and you can start earning your blue points.
Second, blue points are far harder to earn. There’s a lot less things that reward them.
Early on, studying items at the desk in the church basement will be your first infusion of blue tech points. Unfortunately, you’ll need to start earning Faith from church sermons first, as they will fuel your studying ability. Body parts from autopsy will be your friend here. Your tools also award some blue points when studied (but they require slightly more Faith to study as well). Another excellent early source of blue points is already in your graveyard - those gravestones, fences, and statues! Use a little energy to temporarily remove them, study them, then put ‘em back. All the stone ones award strictly blue points, and the stone cross in particular awards a nice chunk.
Don’t forget to study each new item. Feel free to prioritize items that award blue tech points even if you haven’t earned the red/green achievements yet; trust me, you’ll earn red and green points easily. However, looking at a list of Alchemy items that can be converted into Alchemical ingredients will be useful; you’ll need to study any such item first before it can be transformed for Alchemical use.
Finally, once you are finally able to harvest Dark Body Parts (not until you’re nearly done with the Inquisitor’s quests), these are a crazy good source of blue tech points, as are the Alchemical ingredients they create.
However, you’ll likely find you still need more blue points even once you’ve researched just about everything. This is where it gets grindy.
There are a select few items you can craft that award blue tech points. First off, and easiest to craft, is glass. Glass is very simple to craft (only requiring two ingredients, sand and water, both of which are infinitely harvestable, plus fuel for the Furnace) and awards 1 blue tech point per piece crafted. As you unlock further glass skills (conical glass and advanced conical glass), you can proceed to craft each successive glass item with your previously crafted ones for more blue points each time. And speaking of glass, there’s one more item you can craft at the Carpentry table for blue points - Lenses.
Next, starting with the new items you can craft once you obtain the Stonecutter II table, you can earn blue points from crafting certain gravestones and stone fences (namely, the ones that award 3 or more GR). Statues also award blue points, as does creating the carved stone required to make them.
Be prepared to work for a while for these blue point achievements.