There are certain criteria for doing well on “American Idol.” You’d think that, after two previous seasons, every single contender would know what they are. After watching last night’s round of eight, the lamest group ever, it’s obvious that they don’t.

For them, and the next group, and anyone considering going on the show in the future, I hereby offer my Ten Tips For American Idol Wannabes:

1) You must be able to sing. This one should be painfully evident, but it’s clear that it’s not. Some of the so-called singers who made it to the final thirty-two couldn’t find a note with a telescope. If they sang like that at the audition level, they would have been kicked out faster than Brian Dunkelman.

2) Choose the right song. If you have tattoos, piercings, spiky hair, and leather bracelets, do not sing a gentle Norah Jones song. You’re a rocker, so pick something that rocks. Similarly, if your look and attitude say “hip hop,” stick with that. Do not try to show the world how versatile you are.

3) This is a pop music competition. Along the same lines, no one wants to hear how well you sing another genre, like jazz or country. Do not try to outdo Patsy Cline with “Crazy.” Don’t even sing a country song that was recorded while you were alive. This ain’t the Nashville Idol contest.

4) Perform songs everyone knows. This may be the only time you’re ever on national television, let alone have an opportunity to show everyone what you’re really capable of. Wait until after you’re a huge star to perform your tribute to Nina Simone. Until then, emphasize your strengths and sing something the home viewer — who will have to vote for you — immediately recognizes and probably likes. It could be Motown, Nirvana, Elton John, Jennifer Lopez, Mariah Carey, Sheryl Crow, or even a Huey Lewis hit you heard in kindergarten (these kids are all under 26!).

5) Do not pick iconic songs. While the song should be very well-known, it should not be so identified with one performer that, by comparison, you can’t possibly look good singing it. For example, avoid “Imagine,” “Wind Beneath Your Wings,” “The Greatest Love of All,” “What’s Love Got To Do With It,” and “I Feel Good.”

5) Stop with the ballads. ‘Nuff said.

6) Pick the right clothes. If you’re at all plump, do not wear a midriff-baring shirt, or one that might show off your gut even a little when you raise your arms. This goes for men as well as women. While we’re at it, no hats, either.

7) Don’t overdo the vocal runs. There’s no reason to insert extra syllables into a lyric just to show off how many different notes you can hit in the word “love.”

8) Be humble in defeat. If your performance is terrible and Ryan asks you if you have anything to say to convince the viewers to vote for you, do not say, “It only gets better from here.” It would have to, because you stank up the joint. But you also blew your shot. We don’t want to hear you’ll be better next week. You had this week to impress us, and since you didn’t, you can become one of us on this side of the screen for next week’s show. On the other hand, it will get better from here for the viewers, because you won’t be on the show anymore.

9) Avoid controversy. No matter what you do, do not sing a Michael Jackson song. Seriously. You also probably want to stay away from Janet Jackson’s catalog. And anything by R. Kelly, too. And just on principle, Courtney Love.

10) Don’t pick a fight with Simon Cowell. Not only is he the real star of the show, but Randy Jackson is just as vicious! The teen girls who surround the stage (looking up at Ryan Seacrest, wishing they could just touch his hair for a second) seem to ignore Randy’s brutally honest comments, but if Simon says anything at all negative, they boo him. Randy gets away with it by dropping in the word “dawg” three times in every sentence. Bottom line is that neither of them is dissing you just to be mean. If they say you sucked, you did. Moreover, if even Paula Abdul can’t come up with something nice to say about you, you should seriously consider never singing again.