The cottage economy is probably the most straight forward.
Ideally, you want a capital with plenty of grassland and flood plain. Without flood plain you definitely need a food source. Civil Service is a priority for Bureaucracy. Just work the cottages as much as you can so they grow, and build the oxford university and an academy there. You should try to get a great scientist early for the academy, usually from a different city (otherwise your cottages probably aren't growing).
A financial leader is easiest ... cottages on riverside tiles start at 3 commerce right away. At noble level, on standard maps and smaller (maybe larger maps too), just concentrating on cottages in the capital with Bureaucracy, an academy, and oxford, you will tech far faster than the AI. You can probably be killing musketmen with tanks, and I would not be surprised if some AIs still didn't have alphabet when you get liberalism. You just have to make sure you have other cities for production, and build enough military. Eventually you will be ridiculously ahead in tech.