require suggestions from everybody on kernel modules programming

["bunty " <bunty123_4@xxxxxxxxxxxxxx>]

 
Hello all,
  While doing kernel module programming i come to know following aspects that we must not use in kernel modules
1)#define MODULE
  #define __KERNEL__

2) dont open files in kernel modules
3) dont allow kernel modules to sleep

Is that correct? As far as i  have interacted on kernelnewbies and its archives said its correct.
Please provide your suggestions and also what should not be done in kernel like aboce things???

Thanks in advance.
regards,
parag.