Just keep one thing in mind before you pull the trigger or release an arrow, is he really worth the effort of a solo pack out. Been there! 2.5 days later and sore knees. As long as the weather permits, it's still all fun and rewarding.
Use all possible tactics. Call, spots and stalk, ambush, and dumb luck. Being a purist is a good way to go 0 for 4. Might be you use a couple of these at the same time, like a lone bull that is bugling, and you can stalk him because he keeps giving you his exact location. Throw a cow call in to keep him calling, and seal the deal. There isn't one way to get it done.
Pay attention to the setup. Visibility when calling is good for both you and the elk. It will hang the elk in a lot of cases. Force him to come to you with terrain, thickets, blowdowns, etc.
Don't forget a small tripod like a gorrillapod for the grip and grin photos. Learn to use your timer on the camera.
Quick follow-up since there are some recent responses: Hunt went great, killed a bull on day 3, pack out was around 1.5 miles, a mile of it was downhill on a logging road. Small spike and was able to get him out in 2 trips. I could definitely see more work with a larger bull. Going back in 21, most likely solo again, so we'll see how it plays out.