Thought injection

the chances of this spell's success depends on your abilities, power, and the target's mental defenses, trying to understand how your target thinks will help you to inject more convincing thoughts. 
you can not use this spell to make someone do anything against their core values, the brain will simply remove the thought if it was too odd, for example, you can not use this spell to change someone's religion, or to make him your slave ... but you can use it to make him like a new activity or hobby or slightly change his opinion on someone.
use it morally.

1) create a comforting atmosphere, meditate, gather energy, and visualize a syringe, this syringe should be made of any type of metal and look metallic so that it can penetrate mind defenses. 

2) fill the syringe with transparent fluid with a taint of purple to it, purple is the color of thought and psychic power, so this will look like normal mental power. 

3) visualize a psi ball, and turn it into a bubble, this psi bubble will burst and cause no harm once inside the target's head. 

4) now concentrate on the thought you want, think of it, see it's effect, imagine any voice, smell, taste or any feeling linked to it, and even believe in this thought as your own thought, this will be the thought you'll inject in the target's brain. 

5) now concentrate into removing that thought from your head, and put it inside the psi bubble , this is the hardest part and could need some practice. 

6) put the psi ball inside the syringe, let it settle in the middle of the liquid with nearly half the liquid below it, and half the liquid above it.

7)  (optional) before you move to the next step, send prayers or chants to any god or entity you worship, if you do not follow any god then try asking the power of mind, or mental spirits, for help, if you do not know how to chant try this simple chant : "oh (who ever you ask for help) please make this succeed, I am doing it because I'm in need, I ask for you to grant me success, for this action, no more, no less", any outside power will help you with visualizing, luck, and overall success rate, tho you can skip this step.

8) now keep visualizing the syringe, and go to your target, you must be close and able to see the target for better effect, tho if your psychic abilities are strong you can do it remotely .... now imagine the syringe penetrating the target's brain, and slowly let the contents of it flow in your target's head ... start with the fluid to disguise the spell and let the brain not be wary, then inject the thought, then the rest of the fluid these steps mask the thought and make the brain less suspicious of it as it thinks it is receiving mental power/blessing.

9) if the psi bubble does not burst on it's own, then visualize it bursting.

you should see subtle change in behavior in few minutes, but give it few days to have full effect, it will mostly grow in power each time the target thinks or sleeps.