1) I rarely take a mission to a destination farther than 5000 light seconds from the arrival star.
2) I never use the forum recommended Supercruise technique. If you're throttling down seven seconds out from your destination, what you're doing is extending what should be at worst a thirty second braking period by up to two minutes, depending upon the arrangement of mass at your destination system.
If you want to reduce the amount of time you spend in Supercruise, what you need to do is take advantage of the braking effects of mass to slow down your ship. When approaching your destination, don't throttle down until five seconds away, and try to get as close as possible to whatever planet your station is orbiting, without hitting the orbital cruise or exclusion zones and getting dumped to normal space. Here's an example of what I'm talking about. Even if you don't get close enough, overshooting your destination and looping back is still faster than throttling down at your destination.
It requires hands on piloting, I personally find it at lot of fun, and you get the satisfaction of getting to your destination a lot faster than most players. Plus, as a bonus, it reduces your window of vulnerability to being interdicted at your destination.
When I do decide that going to a distant destination is worthwhile, until Tuesday I just kept an eye out for USSs that spawned along the way, and visited the high-grade ones along the way. Tuesday is when 3.3 is released, and how USSs spawn will change, so they'll be less likely to spawn along the routes I take.
Keep a close eye on instrumentation (such as it is) and learn how your ship handles in different situations and how responsive it is in Supercruise. Zone out to the sounds of your ship's hull integrity and paintwork falling apart as you travel long distances. Manage your power consumption by turning things off and on when starting / stopping a cruise, eg SRV bay.
