have a few question on evasion if you can help clear up:

1. If I power up my character with cards like savage beatdown and declare an attack on my opponents character with evasion, if my opponent uses the evasion effect, does it ready my character and I lose the +5 attack and I have to declare another attack. If this is right, just let me know, if wrong, please explain correctly.

Still learning the game and some of the card texts are messing me up a little bit, very fluent in yugioh but not so much in versus, thanks

Well, you would have to play Savage Beatdown during the attack, since it only works on an attacker. But yes, if your opponent evades, your character would ready, and your little bonus from Savage Beatdown would go away.

that sucks, i hate when my friend knows something i don't, thanks

take a look at cards like Flying Kick or Mega Blast... they grant the bonus for the entire turn.
if your friend is playing characters with Evasion, you might want to play some of those over the otherwise more powerful ones that only last for the attack.