What would you do if you found that your mind has more negative things than positive?
One way is to use positive words to counter them. You can enhanced it by imagining positive outcomes as well. Work with words and your imagination to bring more light into the mind to dominate the negative thoughts.
Negative things exist in our mind or our life for a reason. It is not at all that bad. Unless you like the experience of negativity, then you need to change your thoughts to change your world.