There are several different private farms that I hunt - some of them owned by family and most others are close enough to be (or closer than) family.
I always make it a point to help out on any farm work or projects that arise when I'm available or around. Sometimes I help put up hay, I've put up cattle when they've torn down fences and said landowner was out of town, I've run equipment and cleaned up fields.
One dairy farmer was having a bad pigeon problem in his free-stall barn. The pigeons were building nests in his fans which eventually caused the motors to burn up or ruined a blade and cost said farmer several hundred dollars a pop. I took care of a whole mess of pigeons for him and he hasn't had a problem since - good shooting too.
Also, I always make it a point to invite landowners to hunt with me if I know they do any hunting at all. Some guys just like to watch the dogs work.