i have been playing all this week but i notice that all my opponent has to do to beat me is lob a pass to the other side of the field and no one is there to take him down! he gets an easy shot.
this happens to me often. do i need to choose sidekicks that are defenders only or is there a trick to always have someone there?
also how do i lob it across field like they do?

To lob you hold the Z button while passing. To defend it's easiest to have one of your players near by and pressing A to intercept the ball. As for side kicks I prefer to have one as a defender but that's just my personal preference.

What does the make-up of your team look like now? Having defensive players in the defense position looks good on paper, but so does communism. Describe your team and maybe we can give you some pointers.

Hey Big O

my team is dry bones and hammerbros for front and birdo at back.

also im having trouble with hammerbros spammers.

THNX

Rudy

What's your captain, buddy?

Doesn't the A button just change your player? I always press B to intercept. Am I doing it wrong?

Sounds like your to enthoustiastic to get your players to his side of the field!

Dont get all your players there. Leave the defender at your side!

If hes lob passing trie to stand in front of him and press A or B to intercept the ball. Also a good tackle helps

You are a little confused it seems. The A button changes players, passes, and intercepts lob passes. You can use the B trigger to fire off lob passes as one timers, either from your own teammates or his if you can catch him.
Cyberzomby sounds like he may be right, you might be a bit eager to drop your defense, resulting in poor coverage.

hey yo,

my captain is bowser

how do i make a character stay on my side? since my back is birdo, does that mean i dont use birdo when crossing to the opponents side.

THNX

p.s i didnt know you intercepted a lob with A!

Birdo, despite being a "Defensive" player, really has no business in the defenseman position. She's much more useful in the wings. A playmaker does very well in the defenseman position, but if you want a Defensive player back there Dry Bones wouldn't be a bad substitute, although I personally believe 'ole Bones belongs in the winger position as well.
You shouldn't be taking control of your defenseman to cross into enemy territory unless you've got a clear lane and are going to attempt a Systematic shot or chip technique. Other than playing smart coverage and not charging the ball all the time, there's no way to control your sidekick's shifting. Sometimes they'll just open themselves up, but that's why it's good to have someone fast back there to quickly get back into defensive posture.
Also, if you're still having trouble with Hammer Spammers, you should practice a common technique I like to call "Baiting the Juke". You're being too predictable, and baiting should put a twist on your defense. It is essentially tricking the Spammer into juking himself wide open. Come at him with a character as if you were going to attempt a slide tackle, only to suddenly change direction just outside the range of his juke. When the hammer drops and he starts to come down, you should be theoretically unharmed, and he will be ripe for the slide tackling.