yes,for doing b-tech the best way to take college is firstly go for jeemains and all entrance exam conducted by government .it will help you to take admission in IIT and NITS...
Besides that there are many best private engineering college with good placement that you can look for and those are......

Anna University, Chennai

Jadavpur University, Kolkata

Birla Institute Of Science And Technology, Pilani

College Of Engineering, Pune

Shanmugha Arts, Science, Technology & Research Academy, Thanjavur

SRM,Chennnai

VIT,vellore
etc etc.

Just focus on mains and advance exam. Try to ge to the best. IITS then nits to central government funded colleges and many more.

For btech you should prepare for IIT's and give JEE mains and advance. IIT and NIT are best colleges for doing btech in computer science.
Other than this you can fill the following college forms:

• Bitsat for bits pilani
• IIIT Hyderabad
• VIT vellore
• SRM

You can fill these universities form they have good opportunities.

Good luck.

For B. Tech in computer science, it is best to choose any Indian institute of technology (IIT).. so all depends on ur JEE Main ranks.. If u want to choose any state University, then tell me which state you are belongs to..