The number one reason we hear from golfers for why they don’t improve is that they lack the time. Yet, if golfers would simply make use of idle time at home or at work – time spent watching commercials, talking on the phone, etc. – they could get a lot more out of their golf games than they’re doing right now.
For the full swing, mirror work is particularly good. Whether you’re holding a pen or a bare grip or a ruler, you can make swings and look at your reflection in a mirror or a window to see what feels create different looks. For putting, you can put two balls down on the ground and practice stroking back and through about equal distances for good acceleration/deceleration in the putting stroke. For the short game, just chipping around your back yard is a great way to get in some time.
Golfers can find more time if they’re willing to work for it.