If your asking about like
how to win using olimar ?
1) check out NC Echo's guide.
2) Pik often,
whistle often,
WAC if necessary but don't spam it,
Fairs are good for comboing
but Olimars other aerials don't have much priority.
[against Diddy and ROB anyways, which were my test subjects]
Forward + b is a god for getting damage,
Whistle before recovering.
Try to have a purple in line next for when your going to recover to stop edgehoggers.
Forward smash is pretty good,
upsmash is best.
Downsmash can help you out if youre surrounded or don't know wher opponent is going to be,
Red pikmin are best for aerials [damage wise] and are also resistant to fire. Fire attacks.
Blu pikmin are best for using in your throws [damage wise] and are water resistant.
Yellow pikmin fly in a wider arc when thrown, and do electric attacks. Also electric resistant.
Purple pikmin don't fly far but do heavy damage in smashes. Also can stop edgehoggers when your recovering. Lives long.
White pikmin fly farthest, appear to do most damage when Latched, but die fast and easy, and do little damage outside of Latching.
Dash attack is alright but has little priority.
Olimar can juggle very well.
Don't get caught above an opponent. Olimar is in a similar posistion as a lone Ice Climber is above an enemy.