The previous post reminded me of an old book I still have. The cover is shown below. Now, don't you see the word God and you think I want to preach you religion and quickly close the blog. No, I don't preach religion..
I think if you want to spread your religion it is better to be a good example yourself and do good rather than going around trying to convert people.
Even if you are not a Christian or whether you believe in any God or no Gods, you can still make use of some of the things it says . Here is one example everyone can use: