The companies that you apply are totally left to you. So before you apply you should have the rough idea about the type of company, its location, salary, bond, probable number of candidates the company requires, etc.
Once you get to know the date, timing and location of the company, the first thing you should do is go to “Google” and then to the company site. Go through their recruitment section; watch out what skills they seek among you, the area in which they work etc.
Then contact somebody who has been earlier interviewed by the same company, or who works in the company or who knows the test pattern of the company. Fetch out sufficient information.

Then sit and decide the subjects you are to prepare; like you may have to study verbal or puzzles, etc. Decide on which technical subjects you are going to prepare and start preparation thoroughly. This should be done minimum of 8 days prior to the interview.
In these days study well. It’s like as if you are preparing for a war. So you should be as serious as hell. Don’t say ‘let me try my luck’. Say always ‘I can do anything and I will do it’.