My advice would be to always leave a "hook" for yourself to use. Not for the Imms to use. Something that may "click" when you interact with other players, but so you can't predict how exactly it may "click". Perhaps a list of wants. What the character wants. Not boring stuff like "I want to become Emperor". Perhaps something that haunts the character. A bad past experience that forces him to behave in a certain way. An impulse that he would act on. Etc etc.
Examples from my own characters:
As Kazzru, my initial role was just an angry thug with a drinking problem. The idea was to explore the "Good is Not Nice" angle, so good-align but with bad temper. I pretty much just wanted to knife people. (I love knifing.) He also had other issues (past failures, alcoholism). I planned against joining the Fortress, but I had a hook about needing a purpose in life, and Andira, Azhelak and Keara pretty much pulled on that hook (without even trying). I had great fun gradually changing my character's personality and behavior, and some of it was highlighted in the role (coming to terms with the past, thoughts on lawbreaking, etc). No Imm involvement (unless you count Andira inducting me / Baer making me an Acolyte at level 29).
As Einrai, I had an initial role goal to get gold to buy my family out of indentured service. A Herald (Tykanis) gave me enough money to settle it, and this had tied me to the Heralds (starting me off as a storyteller in my off-time). Then I pulled another very similar thing out of my interaction with the Sunwarden, Nalaya -- I "bribed" the bureaucrats into freeing her imprisoned mother. There was no Imm involvement, it was all make-believe, although I did hand 1000 gold to a banker to be transferred as a bribe. I also dragged Keara to participate. Then I brought upon a role about disliking elves -- somehow it happened that I had 4-5 different IC conflicts with different high elf characters (an outlander, a trib I uninducted, criminal marans, etc). Also zero imm involvement.
As Kowelu, I built a story arc about helping out orcs, inspired by the form I used most (bonding with orcs through mutual appreciation of biting people in the face, hah!) and it fit the character's outlook super well. The story arc about wanting to become a vampire was inspired by three different people: Tsalantha (who told me vampirism is linked to betrayal), Daphedee (whom I chose as someone I planned to betray) and Sindrir (a phrase I heard from him made the conclusion of the arc). E.g. I refused to go on with the plan because I loved Daph and didn't want to hurt her. No Imm intervention was required.