The best way to do pair trade is to eliminate subjectivity and not really be concerned with which instrument to use. For example you can pair trade with ICICI Bank with Bank Nifty or maybe ICICI with Nifty…as long as it works.
You can do with Nifty and Bank Nifty for index.
For stocks these could be combinations.
INFY - TCS
ICICI BANK - HDFC BANK
HINDUSTAN UNILEVER - ITC