For anyone that will want a challenging start in Victoria 3, the Free City of Krakow should offer one! A tiny Austrian Puppe, a clever Krakow player might make use of its starting laws to become a major economic hub in the Austrian market.
Krakow is a Polish city, which has had a turbulent history throughout the ages. Unlike Paradox developers, players have already made plans to make Krakow the owner of, at least, half the world, and not just an economic force in the Austrian market.
For any goal to be achieved, it needs to be backed by a realistic plan. Furthermore, in order to be sure that at the end you reach your target, players normally prefer a planning methodology ‘from the end to the beginning’, with named milestones defined in time. Such a methodology allows the following of the general progress against the master plan and allows calculation of buffers or delays, should any of these appear.
In the beginning, Krakow will have to rely on its connection to Austria, and leverage it into gaining colonies in Africa. Though these will be table scraps, given away by Austria, they will still be useful for Krakow's early purposes. Furthermore, Krakow has a literacy of 54%, among its population, at the start of the game, meaning that focusing on technology is a wise choice, as even Great Powers of the time have a lesser literacy percentage.
Of course, the whole plan of pushing Krakow to new heights, which is extensive and can't hope to fit one article, relies on certain things falling into place, which are outside of the player's control, at least in the beginning. So, if you wish to play as Krakow, expect a lot of playthroughs before getting the right circumstances.