First of all, I appreciate your future planning. Most students won't have this kind of planning in the first year of intermediate. To get a better rank in EAMCET, you need to understand almost all the concepts in Maths, Physics and Chemistry and do some hard work.
Many students of your age won't raise their doubts in the class. It is a must to clarify all your doubts from your teacher. Not clarifying your doubts may be given an excuse in the second year of intermediate but not in the first year of intermediate. Most of the second year syllabus is based on first year syllabus. If you don't have a proper understanding of first year syllabus, you can't have a proper understanding of second year syllabus. So, make sure that you clarify all your doubts by raising them in the class or at least after the class. As Maths is for 80 marks and Physics, Chemistry are for 40 marks each, try to give the highest priority to Maths. In case you feel that you are poor in Maths, give equal priorities to Physics and Chemistry. As there are no cutoffs for Maths or Physics or Chemistry, you can give highest priority to the subject or even a topic you are interested in. It is better to know some topics perfectly instead of knowing all topics lightly. Finally, practice different models of problems so that you can answer about 50% of the questions immediately after reading them.
Start the exam with your most favorite subject. If you start with a subject you find tough, you can get discouraged and that won't allow you to answer the questions of even your favorite subject better. As you should answer 160 questions, time management is must. Keep a digital watch with you. Make sure that you don't spend much time for a single question. If you feel that a question is too tough, just circle it's question number so that you can try to answer it later. If you feel that a question is wrong, draw a square on that question's number. After completing the entire paper like this, start referring the circled questions. Try to answer each of them two times. If you can't, draw a square on their question numbers. Note that you have to fill the OMR sheet after finding an answer or at least ten answers. Filling the OMR sheet at the end of the exam might lead to bubbling mistakes due to tension. Finally, calculate the number of A's, B's, C's, D's in your answers. As there is an equal probability for each option in EAMCET, you can answer all the squared questions with the option that is least used till now. Note that this technique should be used only in case of emergencies like out of time etc,. By following all the above tips, I got 8839 rank in EAMCET even though I am suffering from health problems then.
The top five branches of engineering are:
1) Electronics and Communication Engineering
2) Electrical and Electronic Engineering
3) Computer Science and Engineering
4) Civil Engineering
5) Mechanical Engineering
Depending on your interest, you can decide what branch you want to select. I personally recommend Computer Science and Engineering as there are many jobs in the field of computers. Coming to the colleges, prefer government colleges to private colleges. You can learn by choice in a government college whereas as you will learn by force in almost any private college. Also, the fees is less for government colleges.
I wish you all the best for your future. Hope you get a good rank in EAMCET and study engineering in a college and branch of your choice.