It depends on what you're doing, because there's a fine line between designing and "making things look pretty". Designing is a lot of concept and understanding what you are doing, who you are working for, what the message you want to portray. It's a lot of business and thinking before anything hits paper or the computer.
But if you just want to make your WDYWT pictures look "nicer" I say get Adobe PS and look for online tutorials about how to apply a filter.
Not being mean, but I'm a graphic designer (yes, dime a dozen we are) and I see a lot of trash and people calling it design.
Whoever appeals to the law against his fellow man is either a fool or a coward. For whoever cannot take care of themselves without that law is both. For a wounded man will say it his assailant, "If I live, I will kill you. If I die, you are forgiven." Such is the rule of honor.