You can use mindfulnes as a tool to help you change the way you look at the world, there are several key attitudes to adopt. Most notably is

Non Judgement This attitude change requires working on the ability to observe a thought or feeling like a cloud passing by instead of making judgements about yourself such as 

you could be thining something like "I'm a failure for being stressed" but instead you could just simply note " I am feeling stressed right now". Which is a much gentler way to be woth yourself.

The Beginners mind This attitude requires you to practice approaching people and tasks as if you've never seen them before. Doing this as much as possible helps to prevent us from living on auto pilot.

Non Striving Unlike most things in life, mindfulness isn't about 'getting somwhere' you aren't trying to force yourself to be calm, or to achieve anything, instead you are simply noticing how you feel.

Breathing " Even if you only stop and focus on your breathing for a few breaths , or for a minute or two , it's very valuable"

Thich Nhat Hanh - Making space.

The Anchor breath. Find a comfortable seat. Focus entirely on the physical sensastion of air entering your nostrils or the rise and fall of your belly ! 

Your mind will wander- this isn't failure  that's the exercise! Every time you notice your mind has wandered and you bring it back to your breath you have done one rep, episode or example of mental muscle building.

The Body Scan Lie down and mentally scan your body from your toes to your head. Notice tension, tingling, or temperature in each area without trying to change it. This builds a strong mind - body connection.

STOP Practice This is an on the go technique for stressful moments. Stop what you're doing, Take a breath, Observe your thoughts, feelings and physical sensations. Proceed with whatever you are doing, but with more awareness.