The Personality Traits seem to control what your animations are pre-match and between the entrances. For example, when my character has a high Egotistical (or whatever the first heel trait is; I'm going off the top of my head), he smirks before the next person is introduced.
It also SEEMS like the early choices in MyCareer control what your interview options are later, but I haven't run through enough times to confirm this.
Take the Resiliency special ability. Do NOT use your finisher as soon as you get it, particularly if your opponent isn't on his/her final health bar. Instead, save the Finisher for a "Break Glass" moment, specifically the opponent hitting their finisher. Don't use the finisher until you are ready to finish the match (it's weird to say that, but holding back goes against "video game instincts").
One other helpful Gameplay hint: Particularly on non-Legend, this game becomes a function of Reversal management. As long as you have as many (or more) reversals than the computer and you can fairly consistently reverse (assuming you get a reversal at least once every three attempts), you can set up a highly-advantageous scenario. Here's the deal:
Immediately perform a running strike or grapple at the beginning of the match. It doesn't matter if the CPU counters or not:
If the CPU does not counter, you have initial control. Damage them until the computer reverses. You then reverse back. As long as you have an equal number of reversals, the CPU will run out before you do.
If the CPU DOES counter, immediately counter the next move. Again, as long as you have an equal number of reversals, the CPU will run out before you do.
Fun time occurs once the CPU runs out of reversals. Based on the above paradigm, you should be able to take control when it runs out. You have free reign to attack with the computer unable to defend itself.
The ONLY time I've ever seen a reversal when one isn't there has been when spamming the same strike to a grounded opponent (i.e. the fifth stomp in a row seems to be auto-dodged).
You're not on the "correct" part of the apron. You must be standing on the apron and in your corner. Your momentum will slowly go up if you are standing in your corner not doing anything, and slowly go down whenever you are not... even if you are just standing on the middle part of the apron.
I don't THINK it lowers your relationship with a potential partner when you are in the middle of a rivalry. I /BELIEVE/ it does if you in theory can do something with your partner and choose not to.
EDIT: I was wrong. Though it doesn't seem to drop you out of a tag team, the game does lower your relationship if you don't cultivate it.
So, from what I saw, at least once a month, before you start a rivalry, you second your partner for a match. That kept my tag team going for... well, longer than my attention span for keeping the team.