Be warned that some of these tactics are quite gamey. There are obviously quite a few more but these serve as good examples since both of these are extremely difficult to survive, much less do well with, so I pull out all the stops as I will outline below. To that end, a couple of interesting vanilla map starts in 1066 are the Count of Napoli, who is the only Greek Orthodox in Italy and Lübeck, which starts nestled between three incredibly strong powers and a single county with a claim next door. I tend to go for ahistorical conquests, as radically different from history as possible. (For vassal dukes and kings, the bonuses are +25% for capital, and +15% for capital duchy). In addition to the capital county bonus, independent dukes and above get a +25% bonus to levies in their holdings within the capital duchy. Note that independent counts get a +50% bonus to their levies in their capital, while vassal counts do not get any bonus.
But if you start out as a vassal, your first goal will probably be to take over your liege's lands, so if that's not the direction which you want to go, an independent start might be better. This is a guide to my preferred start, which is almost always as a count or as a small duke in 1066. This article is timeless and should be accurate for any version of the game.
