"I have started" is correct, but what would you be talking about? "see" or "seeing" is really only used in reference to sight, and also to understanding. "I see" would mean either "I can see something in front of me" or "I understand what you are saying"

"I have started to see." is correct. "I have to start to see." is incorrect. I must start to see. More information about what you are starting to see would be helpful.

"To see" is an infinitive verb that is open to many interpretations. Let's change it to "to like" I have started to like >" I just not long ago untill now start to like (something) " I have to like > "have to " = need to / must (to) /got to/ > You must -- because of a reason not mentioned, or maybe you are being forced- to start liking (something). I have stated to see her often now because I have to or else her father will kill me .