Hey Jiten..
I am vipul working with Cybage Softwares,Pune.
Actually I am working with white box testing...but i am intrested for black box for my next project.....lets start

I am a developer so i don't have idea of the practices for black box testing. But i think this should be considered while testing:
- Before starting the testing, one must study the application requirement document in detail so that he/she has good understanding of the application.
- While creating test cases he should take care that test cases are written considering the setup environment specified in the requirement document (OS, disk space, memory etc.)
- While creating test cases he should take care that test cases are written for all the requirements.
- While creating test cases he should take care that the test case maps to current requirement and is not an enhancement to the application.
- Including destructive test cases (scenario which may not occur on regular basis but have chances to occur) is good, but a limit should be set for the same.

-Pradeep

while developing test cases a tester has to
make sure of covering all requirements
develop -ve test cases also
make sure to use less no of test n cover most of the requirements.....for this u may use different black box testing techniques which help u choose inputs that will cover both +ve n -ve tests.......
make sure of considering the test enviornment.......ie. h/w n s/w requirements of the software...........
there can be more but these are a few ............

hope it prooves usefull to viewers!!!!!!!!!