If you enter at the same time every day and haven't won in a long time, change up when you enter - or even in what order you enter.
Keep in mind that while winning is the goal, interacting with other sweepers in the forums and comments is a side benefit that will make you feel like a winner!!!
Dry spells CAN be broken, so don't give up!!! However - if you are starting to feel burned out, take a break - sweeping should be fun, not a chore!!!
I save winning pages to paint, so when I'm blue, I can revisit past wins and reaffirm that I AM a winner - you'd be suprised how such a simple thing can really lift your spirits!!!