How to reduce negative mental patterns?

Here are the most useful activities to reduce negative mental patterns:

Keep a gratitude journal wherein you write down three good things that happen to you every day.

Sincerely appreciate and thank others for traits or things they do-- try to do one of these a day.

Regularly reflect on what you have to be thankful for (people, experiences, objects)-- try to do this once a day.

Recall happy memories of yourself and with others.

Find the positives from a negative event that happened from your past, or choosing not to be disappointed by something in the present or past. Hard mode: try forgiving someone and talking to them about it.

Write a letter to someone who changed your life in some way, expressing how what they did was meaningful to you.

Celebrate small achievements, for yourself and others. Spend time doing something you / they like as a reward, or throw a party or appreciate them in some way.

Select those that you feel are most relevant!