Mindfulness means to live in the present. People often get obsessed with their past mistakes and this affects their future. Here are some tips to be mindful of:

Reorienting yourself to the present moment
When stress for the future occurs, remember your present is the one thing you can control.
Being grateful of the positive aspects in your life 
Count your blessings and remember what is important. It's not that happy people are grateful. It's that grateful people are happy. 
Meditation
Just a few minutes every day can help with your attention span and sense of inner peace. 
Deep Breathing
Breathing exercises are especially useful during panic or rage attacks. 
Being aware of what triggers your anxiety
Avoid and manage your anxiety triggers. Stress has shown to increase your chances of developing hypertension, diabetes, obesity.
Enjoying the Moment
Enjoy reading this article. 
Accepting Reality
Unrealistic expectations is often the reason for unhappiness.  

Skipping Breakfast
While skipping breakfast may seem like a good plan, you end up increasing the stress hormones in your body by eating at a irregular time. As a result, you may compensate with increased calorie intake in later meals.
Relying on Fat-Free Labels
The labels on these food often don't give the complete picture of what is being eaten. To compensate for the bland taste, it may add even unhealthier artificial sweeteners.
Setting up a short-term goal
Weight loss is a process. It's a lifestyle modification including dieting, exercising, sleep habits and stress management. You cannot expect this all to happen in a day, so take your time and set a long-term goal. You won't regret it.
Getting frustrated
One of the most common cause of diet failure is people concentrating too much on the numbers. Remember that with lifestyle changes, you're getting healthier as well, with your immune system, weight loss, and more. 
Giving up
Lots of people have an unreasonable expectation of how fast the weight-loss will occur. Remember that 4-8 lb per month is decent weight loss and sustainable,
Following Fad diets
Not all diets are equal, and it depends. Do not be tempted by clickbait titles as there are many factors that play into weight loss more than "CLICK HERE FOR 50  POUNDS GONE". Sit down with a doctor to find out the best plan for you.
Getting Stressed 
Stress plays a huge role in your hormone system. How you manage your stress has a lot to do with your behavior, the choices you make, and especially in the path to a healthier life,