I think being in control of your own mind is a good thing, you never know if its safe in someone elses hands
i think, that a good thing is flexibility, allowing your mind to be open to move, you can be in control and yet go into unfamiliar territory, for that is where you learn new things.
My control is to keep as open minded as possible and thats not always easy, but its something i try to do.. Looking at things from outside the box gives you a greater perspective and i find that sometimes to maintain a clear mind so i can focus on something, i become the 3rd party, detach emotion and look at things from a non emotional point of view, that way i am not thinking about how its making me feel but the good clean hard facts and exploring from there...
Regarding clear mind state, i just take the emotional side of me and make it step out, then i have a free mind / clear mind.... if i feel i want to relax to a deep stage / state, i first detach the emotion, then i can go inside myself and become more aware of whats happening inside and slowly calm each place into a relaxed state, its like i slowly put everything to sleep, imagining each part ina perfect deep sleep...
I also give myself commands when i am doing this, that my body will take its time to restore, to repair, to rejuvinate, to file what it needs to file, to clean what it needs to clean and to bring back with it a feeling of pure calm, yet have the energy, the intelligence, the flexibility to be called upon when it needs it.