Be careful with Macros! Use them cautiously
Take the time to build / write test harnesses for debugging your PICs
Check all of your solder connections...cold solder connections should be checked before hours of software debugging...
Don’t be afraid to start your code over if you seem to have an obscure error you’ve spent far too long debugging
Start simple, add complexity as you have time.
Constantly check your code...just because it worked last night doesn’t mean it will work tomorrow morning.
Nothing is working...did you plug in an oscillator to your PIC?