Pro 3:9 Honour the LORD with thy substance, and with the firstfruits of all thine increase:
Pro 3:10 So shall thy barns be filled with plenty, and thy presses shall burst out with new wine.
We go from thinking about God first when making decisions to honoring God with our "firstfruits." This doesn't have to be about a literal set percentage of funds that we set aside for God, though all money is His. Our best work and our love and resources should be for God.
Applied to money, we should remember it isn't ours. If everything is God's, then that would include money. We should arrange our finances in such a way that we are able to think about God first and what other people might need, as opposed to spending all of our money and then if we happen to have some in our pocket when the donation basket goes by then throwing a few quarters in. Contrary to "common sense," I've found that arranging my budget so that the money I want to give away is the first line item (meaning no other money is dedicated to anything prior to it) has made my finances a lot easier to manage. I've not been stressed about money since making that decision. My barns have been filled with plenty. Of course, God would deserve this from us even if there were no reward. He did give us life and send His son to die for our sins - it is not unreasonable to think that we should apply our resources for His kingdom.
There are other resources too. It can be really easy to cut a check and send it in, or even better, have it deducted automatically! If I never see the money anyway, it doesn't get noticed. I'm not so much a cheerful giver but more of an adept planner with a spreadsheet. I can also give my time, through helping at church or just helping others. It doesn't need to be part of an organization. I can also pray! Sometimes, there's nothing else to do but pray.
God is the source of all of our talents and all of our income and all of our resources.