Okay.here we go :
1. Do things out of the goodness of your heart. Don’t seek a reward to acquire things from people.
2. Understanding that sincerity comes from your heart. Eg : you cannot be sincere if you say you like chocolate when you hate it. So, you can be sincere if you truthful to yourself.
3. Realize that sincerity can expose you.
4. Use positive affirmations. Try to place yourself in the other person. Sincerity thrives on effort to think the right way.
5. Don’t over-polish things.
6. Smile always, be positive.
7. Ask yourself if your actions are being done to get noticed.
8. Don’t worry if you have been inconsistent. Sincerity takes time to nurture.
9. Beware of pretending to be sincere. False sincerity is easily detected.
If you are being honest all the time (which you should be), there is no need to use these kinds of.