For many years I have been impressed with Brad Gilbert's ideas on winning tennis dirty. It doesn't mean unfairly - it just means you do whatever it takes (within the rules). This is especially effective when one's mental prowess and tennis IQ are limited by lack of physical attributes. It's my mantra.
I played the other night for the first time in 3 months. With my spring league, there are 2 doubles courts and 1 singles. I gladly took the singles because I didn't want to have to keep apologizing to my partner for incredibly poor and rusty play. And rusty it was. A few shots pleased me - but I mainly just tried to keep the ball in play. It was nighttime, and I started using the lob a whole lot, hoping that my opponent would lose the ball in the lights (and she did a few times). Dirty.
After the match (which I did win!), I was talking with some of my teammates and a couple young guys who are pros. We discussed strategy and interacting with your opponent. I commented, "If I think she's not calling the lines that accurately, I always ask her what she does for a living during changeover, and then I volunteer that I'm a minister. People hate to lie to a minister." One of the pros responded, "Man - that is a great strategy! I'm gonna start doing that." One of my teammates then said, "But she really is a minister."
Kinda fun to see the looks on the guys' faces. But they did agree that saying you're a minister (whether it's true or not) is a pretty good way to win dirty.