Lots of ways to skin this cat, but here’s what I do for my flatbed trailer.
http://www.macscustomtiedowns.com/ makes very good products (and custom lengths too), so keep them in mind.
Front axle straps 97" long (custom ordered, $25 each). Over the A-arm, but under the tie rod, then forward. Being this long, the ends are in front of the splitter to make winch clevis hookup easy. Once on the trailer, I unhook from the winch and crisscross with ratchet straps to corner D-rings. Once crisscrossed, the axle strap D-rings and ratchet strap hooks are under the splitter.

Back—axle straps with Mac’s fleece sleeve protectors on 9.5” wheels (I got their “old logo” fleece for $5 each).
I converted the ratchet strap to a direct bolt-on snap hook because my rear D-ring is close to the back wheels. Since the D-rings are on the trailer edge, they pull slightly off center, but I’m hoping that doesn’t hurt anything.
This is a lot easier to do than axle straps around the differential—I’m getting too old (ok, too lazy) to crawl under the car on the trailer.

Also get their big duffle bag. It easily holds all your straps, and has some plastic panels in the walls for structure, allowing it to stand on its own.
In the future, I’ll look into raising the winch cable over a roller so its bumper height, allowing me to use the tow hook to pull the Boss onto the trailer. Then I’d also use axle straps thru the front wheels as well, and maybe add VersaTie track as an adjustable anchor. But getting the straps around the front A-arm isn’t too difficult.
http://www.macscustomtiedowns.com/ makes very good products (and custom lengths too), so keep them in mind.
Front axle straps 97" long (custom ordered, $25 each). Over the A-arm, but under the tie rod, then forward. Being this long, the ends are in front of the splitter to make winch clevis hookup easy. Once on the trailer, I unhook from the winch and crisscross with ratchet straps to corner D-rings. Once crisscrossed, the axle strap D-rings and ratchet strap hooks are under the splitter.

Back—axle straps with Mac’s fleece sleeve protectors on 9.5” wheels (I got their “old logo” fleece for $5 each).
I converted the ratchet strap to a direct bolt-on snap hook because my rear D-ring is close to the back wheels. Since the D-rings are on the trailer edge, they pull slightly off center, but I’m hoping that doesn’t hurt anything.
This is a lot easier to do than axle straps around the differential—I’m getting too old (ok, too lazy) to crawl under the car on the trailer.

Also get their big duffle bag. It easily holds all your straps, and has some plastic panels in the walls for structure, allowing it to stand on its own.
In the future, I’ll look into raising the winch cable over a roller so its bumper height, allowing me to use the tow hook to pull the Boss onto the trailer. Then I’d also use axle straps thru the front wheels as well, and maybe add VersaTie track as an adjustable anchor. But getting the straps around the front A-arm isn’t too difficult.