How do I stop being so negative and judgemental?

I've been doing some self reflection in the past few years and I have come to realise some things about myself that I would like to change:

1. I am really quick to judge myself and others behaviours an actions quite negatively

2. I realise I can come off as condescending.

3. I can be quite sarcastic, which is not necessarily a bad thing, but I think it is coming out too often.

I have realised I really need to change these behavior as they feed into a negative cycle. I have realised how much it can impact others and it is not really fair to them.

Does anyone have some advice on how to change this mind set and pattern of behaviour?