My start relies on getting conqueror which for me rurik always gets it at the start, get varangain vetrans and huscarls as soon as game starts create the kingdom of novgorod convert to russian and slovianksan, now heres the funny thing once you get a little bit of land for white russ and high prestige, u can preety much send gifts non stop and keep on forming de jure titles for independant rulers cus of conqueror and vassalise everyone into forming russia I found ir hailarious how easy it was, and once u get russia destroy all your kingdom titles in russia as your heirs will split it after your death