In my current Oda game I started as a 2 province kokujin. With a bit of luck I got 3 more provinces in mikawa (1 out of 3 or 4 games the Shiba do not invade mikawa first thus giving time to build retinues), solicited my liege for a daimyo title via diplomatic option which he gave me (note, we had a bethroal going on, might be important). After that I proceeded to expand inside my clan. The Imagawa invaded so I got 2 more provinces from them. Then our clan leader died, I dishonered his son below the threshold, got 3 vassals to join me and broke away. I took approximately 60% of the clan power with me and when he declared war on me for breaking away I finished him off.
You only have very little to do if you don't send your retinue in your leader's campaigns to try and grab the biggest slice of titles you can get.
You only have very little to do if you don't send your retinue in your leader's campaigns to try and grab the biggest slice of titles you can get.