What meditation is best to learn to "control" your mind? I want to learn to in a sense control my mind. By this i mean focus on the thoughts and mindsets that are beneficial. And not focus on the harmful, negative thoughts. I always believe that we are who we are base on are thought patterns and it will be very helpful to in to learn to focus on the thoughts and gain the traits you want and become the person you want. I am learninf jhana meditation. But is this a good fit for this?
Any thoughts, including negative thoughts, are triggered by some stimuli, and have a sensation associated with it.

The best would be to deal with them as per in the Suttas. Suttas like: "Dhātu Vibhaṅga Sutta", "Titth’ayatana Sutta", "Bahu,vedaniya Sutta", "Pañcak’aṇga Sutta", "Sal,āyatana Vibhanga Sutta", "Indriya Bhāvanā Sutta" mentions "18 mental explorations / examinations". This says, essentially, look at the 3 types of sensations (which are, "pleasant", "unpleasant", and "neutral") which comes through each sense door. This helps in prevent the arising of the unwholesome roots due to any stimulus from any sene door. You just have to be equanimous towards the sensation, knowing that they are:


conditioned, and therefore subject to the 3 universal characteristics (or the Pacalā Sutta and Meghiya Sutta imply that it's enough to see impermanence, because if you see impermanence you see the other characteristics)1
dependently arisen based on contact
sustained by the nutriments, contact and mental activity
conditioned by fabrications, of past and present (breath, volitional activity)
tainted by ignorance
etc. see Sammaditthi Sutta



  ... impermanent, conditioned, dependently arisen, subject to destruction,
  subject to passing away, subject to fading away, subject to ending ...


Mahā,nidāna Sutta


  ...  conditioned, gross, dependently arisen ...


Indriya Bhāvanā Sutta


  ... impermanent, conditioned, dependently arisen ...


Parileyya Sutta

You should not do any verbalisation, sub verbalisation, visualisation, etc. when doing the above as this will create verbal fabrications and hinder true and deep insight and cause undesirable results. 

Needless to say to examine the mind you need some level of mastery over the mind, hence is a prerequisite before you practice the Vipassana technique above, since Panna is built on a strong foundation of Samadhi which in tern is build on Sila.




  1
  Aniccasaññino hi, Meghiya, anattasaññā saṇṭhāti, anattasaññī asmimānasamugghātaṃ pāpuṇāti diṭṭheva dhamme nibbānaṃ.
  
  In one, Meghiya, who perceives impermanence, the perception of selflessness is established. One who perceives what is selfless wins the uprooting of the pride of egotism in this very life, and thus realizes nibbāna.
  
  Source: Vedanā in the Practice of Satipaṭṭhāna by VRI