What are the major parameters involved in making a website browser compatible? What are the measures to handle browser compatibility?

basically specify the browsers matrix that u are targetting since getting a 100% browser comapatible is not an easy job and sometimes to get it you will be sacrificing performance...
however following the W3C standards should give a consistent UI on all browsers (check link: http://www.w3.org/standards/webdesign/ ).per testing browsers compatibilty there are good tools that can be used here,unfortuantely the best are not free but the free ones are good like http://www.my-debugbar.com/wiki/IETester/HomePage : this one is for IE browsers.

Thanks for answering, i want to knpw when you start deisgning a page, what do you keep in mind, what major points, you consider?

As Rahaf Nawash said first you need to specify you targeted browser, then you could use tools to help you make you webapp/website as browser compatible as possible, somethings like: modernizr  bootstrap