I have an old post on here that gets resurrected every once and awhile breaking down how to maximize tech. It helps if you understand the entire system, which really takes breaking down the tooltips and thinking about it for an hour or two which most people have better things to do.
You're on the right track, mostly. Although something isn't working right because even in Russia I routinuely get ahead time in tech by about 1250, break tech 4 on schedule before 1350, and an on path to 5 by 1400-1425 (if I actually play that long).
Things to max tech in order:
1. Build max church schools in your demense as soon as the tech penalty goes down a bit (by 1100ish in Europe, longer in Spain or the Middle East). (No need to start focusing on tech at all before the penalty goes down and makes the investment worth it).
2. Occupy high slot counties for your demense, better if they're packed close together. Build cities in every available slot. Do NOT waste slots on extra castles.
3. Make the county with the most cities in it your capital. Many bonuses are based on your capital. It will upgrade first and spread tech from there.
4. Gun for town infrastructure tech 2 on schedule or a little early. Depending on where you play and the basic starting tech of your demense, this usually means around 1125ish -- a few years before the tech penalty goes away. Then build universities in every city.
5. Keep the focus on town infrastructure 3 if the before time penalty isn't too harsh. Upgrade those universities.
6. Do it again for infrastructure 4. You don't need 5 -- it doesn't unlock any great upgrade.
7. If you can grab a few super high-tech counties in Spain or the Middle East early, do it. Once they spread their tech back to your real demense, you can let them go and replace them with counties near your base.
That's a good basic guide. With retinues, I now mostly focus military organization first in military to build a bigger retinue -- although you need to spread your focus in that tab around because every improvement is important. For the other two tabs I tend to leave it on town infra and legalism most of the game, except when the before time penalty is really harsh.
A strategy note: One of the keys you notice is rushing town infra. Getting universities up everywhere (or improving them) 50 years earlier then you would is 50 years worth of a huge tech bonus. If you don't do this, or you don't have cities slotted in your demense to do this, it's hard to compete on tech.
A second strategy note: It often helps to grant all those cities you build in each county to one mayor, who is then rich. (One mayor gets 3-4 cities). He will often upgrade those universities for you as soon as they unlock, saving you a ton of money on upgrade costs. He'll also build ports and the like too, which means more money for you.
