Do Your Research
This is the hard part, but it’s not so much hard as frustrating. You’re going to need to figure out all the exact numbers, meaning how much your blog can bring in within a month, how much you spend on it to keep it going, how much you take home, etc. Take all the numbers and have them written down and it is crucial they are EXACT numbers, not just guessing.
So, dig through all the costs you regularly have like hosting, advertising, everything–then how much you could realistically bring in with sponsored posts, ads, and–everything. Adjust your guesses to be more real is what I’m saying. LOL!