How I can live longer as well as peaceful by doing practices taught by Buddhism?
Here is a list of a few things you can do to live a longer and healthier life. 


Meditate: Stress will make you age quicker and die younger. 
Eat vegetarian meals: Most meats will cause inflammation which lowers your life-span.
Intermittent fasting or only eating for the first half of the day. This will help you keep thin, slow down your metabolism (the idea is animals who have slower metabolisms live longer than those with faster), and your body has the chance to clean out it's system. 
Put aside yourself and help others. Helping other people makes you active, social, younger, and happier.
Simplify your lifestyle. Buddha always encouraged his followers to live a simpler life, why? Because it helps you live longer by lowering your stress and finding happiness. 
Finish all your work in the morning so you can rest in the afternoon. This is a pretty common practice in the monasteries. 
Don't Procrastinate! Buddha encourages us to keep up with our work so we don't add unnecessary stress to our lives. 
Buddha gave us a purpose in life which helps you live longer. We're not just piles of flesh waiting to die.  
Many Buddhist sects believe in early to bed, and early rising. Life becomes much easier when following this pattern of living. Stress decreases significantly! Less stress means a healthy body. 


This is but a few practical tips given by Buddha, with external sources (supporting) the reasons for why you should follow them. I hope this helps and have a wonderful day!