The best advice you can get for breeding to standards, is to start with good rats. Rats and mice have been bred to standard for over 300 years to get to where they are today (mice have had muce more work done). Basically, there is no way to start with pet store rats, and get anywhere near standards. You can breed them for fun for now, but your real goal should be to get rid of the pet store ones and get the best already conformed ones you can find, and improve on them slowly.

And something that a lot of people do, that doesn't make sense, is to breed a good show rat, to a pet store rat to 'improve' the rats. Which isn't good... Instead of breeding 2 good rats together, and getting more good rats, you breed a good rat and a bad rat together, and get 'ok' babies. Which doesn't really get the project anywhere.

This is coming from a prior show breeder!