couple tips that should help:
-first of all if you want you can quit-out, when you get ko'd or tapped immediately guide then quit game, have no idea how many fights can you lose to still get into hof, I went undefeated 40-0 to make sure.
-Make your pro tallest possible- bigger reach, as for the weight class its up to you i picked flyweight, because of great speed/stamina.
-I did this focusing 100% on boxing (bought nothing other than puncherinos), superman punches + elbows to bust up your opponent. Superman punch is your best friend, good damage + very long range then couple body shots,elbows, repeat. Use abilities like heavy handed, targeted cruelty, assault etc.
-Avoid ground game/clinches because AI will counter/block majority of your stuff, submissions are practically impossible to escape on this difficulty, because ai is chea.. i mean blocking all escapes almost instantly, when you are in the hold just quit the game or you lose.
-If they take you down spam left stick to get up, learn how to time the takedown defence (rt + right stick down), it's preety important since you will sometimes get into fights like that:
, yes 26 attempts in less than 2 minutes
-when you get rocked, shoot for a takedown, stand up, repeat once and you should heal up, then go back into spamming supermans
+lil spoiler, along with the achievement you get this