Agree'd with the affiliate marketing side of things.
For example, if you're passionate about new technology (it helps to write about trending topics or products) and you blog about it you could link some cool products readers will actually want, that's a good opportunity to make a commission from the sales, through your product link.
I think it's important to enjoy what you write, as it will rub off on your readers, but it's also important not to blog about obscure things if you're going to be doing some affiliate marketing, just do your product research too and learn everything about that product, it's pro's and cons.
I've done some affiliate marketing, it works but it's a slow process and requires lots of patience and time to see results, definitely do not have a mind-set of making money when you first start, that will follow.