If you allow your character to be faulty, it shows realism.  When someone swings a huge warhammer at you, you can deflect it with your shield, but make sure you let them know it staggered you and made you take a few steps bacl.  This way it lets them know you're willing to be 'real' with it, and it might make them be 'real' with you when the time comes.  That's what I gathered from experience.

Also, just explain what your character is doing, and what they [i]intend [/i]to do.  Never say that the hit connected, because this borderlines on bunnying.  So after your character staggered back from the axe's blow, you lunged forward with your sword and aimed for the opponent's heart.  You didn't [i]stab [/i]his heart, you just [i]aimed [/i]for it.

But sometimes you need to point out why they can't succeed.  You may say something like: your character took advantage of the heavy warhammer's slow speed and lunged for the opponent's heart as he readied his next blow.  The person may or may not agree with this, but everyone knows warhammers are heavy, and even swinging sledge hammers in real life lets you know it takes a lot longer to pull them into another 'attack position'.  So you have the right of realism on your side then.

...

This one time I created a character called a Ziori who used an array of weapons and experience to combat his foes.  Another guy made some sort of over-powered flying reptile-merman hybrid who carried a trident and could control lightning and the ocean.  We despised each other before the RP even began, so we started planning the ultimate battle.  I would have had to travel across two seas and travel a continent to get to his domain, but boy was I ready.

I was going to flee into a nearby cave and let him follow me in.  That would have negated his abilities to use lightning and the ocean, and flying around in a cave would have proved cumbersome.  All he would have had was his trident.  And we all knew my arsenal and skill in combat would have overcome his skills with a trident.  I had a shield, a retracting spear, and two shortswords at my disposal.