Through Anna University Counselling, provided you have good cut-off marks. During counselling there are two type of seats available for PSG Tech, not sure about other colleges. One with Government Sponsored Seat, the other one not sponsored by Government. The main difference between them are the academic fees you pay, Government Sponsored Seat will be around 15k -20k per year whereas the other one will cost you around 55k each year. Hostel fees are same for all students. So be careful while choosing those seats.

PSG also has some reserved seats of their own, they call it as Management seats,you can apply for PSG via this method provided your parents can afford the fees, or willing to sell one of their ancestor land to make you study there.Either one will definitely get you into PSG Tech. Regarding the fees for these seats, Iam not sure about the scheme this year, every course has its own value. If you don't fit into the first category I mentioned above, and still mad to join PSG Tech , Management seat is the only option I guess. And one last point PSG tech offers you a very good exposure, If you dream to become a good engineer PSG tech is a good starting place to build your life as an engineer given that you utilise all the resources and opportunities provided by the college smartly.

Regarding admission for management seat you should be in college right now filling for admission. I see that the demand curve is at its peak right now.

All the Best.