If you have questions about the conjugation of шулер or Russian nouns in general, you can practice and get feedback from a professional tutor.
- Да вы все тут банда шулеров!
You're all a bunch of crooks, but ya ain't cheating' me.
Мой дедушка в свое время был шулером в Гарлеме.
My grandfather used to run a crooked game in Harlem.