If you truly want to be generous, then you have to give just because you want to give, not because you have ulterior motives and want something in return. You should give simply because you want to give, because you've found something you believe in, and because you want to do good in the world.
Be kind to strangers even if you just wave and say hello your being generous.
Give to a cause you believe in. You do not have to donate thousand of dollars a month, just donating 10 dollars a month is generous and when you do it you must realize that you are helping someone who needs it.
Volunteering your time is a great way to be generous. If you want to be generous, then spend at least an hour or two a week volunteering at a soup kitchen, tutoring adults or children, cleaning up a community park