ow much did I like reading it? 5/10

Those advice go beyond self-esteem, it's rather some philosophy to live a better life.
The most relevant to me are:

Ch. 1/ Talk to friends and family

Ch. 2/ See your self-esteem grow

Next, start to build a picture in your head of how you would look and act with high self-esteem. Where are you? Who is with you? Notice the details and enjoy the feeling of confidence and happiness.

Ch. 3/ Write down your worries

The act of writing down how you feel at any given time will not only help you keep track of what may cause a bout of low self-esteem, it is also cathartic.

Ch. 5/ Try a low GI for steady energy

When we eat foods with a high GI (Glycaemic Index), such as white bread, pastries and sweets, our blood sugar spikes and then drops rapidly, leaving us tired, irritable and hungry. Eating low-GI foods – such as beans, rye breads and most fruit and veg – helps to ensure your body is fuelled throughout the day and night, leaving you feeling more balanced.

Ch. 8/ Be naturally sweet

Low self-esteem can lead us to make poor food choices as we try to find comfort from food; sweet foods such as cake and chocolate offer the short-term surge of energy you may crave.

Ch. 12/ Stay hydrated

Water also helps flush your system, keeping your bowels in working order and reducing feelings of bloating or puffiness. Drinking two litres of water each day is generally recommended

Ch. 15/ As simple as a walk

Just a half-hour walk each day can significantly improve your health and emotional well-being.

Ch. 16/ Swim for self-esteem

Swimming is one of the best forms of exercise, because it not only gives you a full-body workout, but also gives you time and space to relax and unwind.

Ch. 35/ Make your goals personal

try to make sure your aims reflect what you really love – be it food, family, art or nature

Ch. 41/ Would someone else say that to you?

Would they say the sort of things to you that you are saying to yourself?
you are being cruel to yourself.

Ch. 44/ Focus on your abilities

try the simple exercise of writing down all the things you're good at.