I would tell you that if there is any subject which you love passionately, just go for it. Once B.S Warrier pointed out that everyone has 2 options: choosing a stream that one loves & loving the trade that one chooses. Its just like marrying the girl one loves or loving the girl one marries.
I am a mechanical engineering student from Kerala. So here are my suggestions. The first year is common for all branches as far as my university goes.
Getting admitted to a good college is very important because that ensures quality education & experienced teachers. A good college can assure better placement, better faculty, better learning atmosphere, better facilities etc. Different colleges conduct their own entrance tests & have their own methods for taking students. Though this scenario will change with the one India, one exam policy which is on the verge of implementation at present.
First let me tell you about my trade, ie, mechanical. this is by far the least complex topic in engineering if one is okay in problem solving & visualizing. Often the mechanical students are referred as ROYAL MEXXX because this is the branch which often sets the standard for college life, ruling the college from the students quarter. As far as the subjects goes, there are subjects like hydraulic machines, graphics, c programming etc. These are very easy to learn once you get the concept. But, the job opportunities in our country for a mechanical engineer is limited. There are excellent opportunities available abroad. Very few girls take this stream.
Electrical engineering is a bit more difficult to learn. It has tremendous opportunities both inside & outside India. It deals with electrical systems, d.c, a.c and the like.
Electronics is the stream with the greatest demand among students. It is a bit tough, but the job opportunities are amazing. There is no shortage of jobs here. If you are into networking & security, the salary package is very high. For that CCNA has to be qualified. It can be studied even after completing class 12.
Computer science is also a popular course. It deals with c, java, boolean algebra, logic gates etc mainly. But unless you want to specialize in this field, you need not take this trade. Because, you can easily jump from any other trade into computer science field, but the reverse process is not possible easily. Once you specialize in computer science, more often than not, you will be getting only jobs in that industry alone, though the pay packages & opportunities are excellent. that is, if you study computer science, then, most probably you will get jobs in that section alone. But, if you study mechanical, you can easily get a job in software field as well as in mechanical engineering field without much trouble.
Civil engineering is an exciting subject to learn if you love designing buildings & the like. It is a comparatively easier topic to learn. Job opportunities are several because of the boom in real estate sector. Here visualizing is very important. Jobs are available in public works department and in real estate companies.
These are the most popular courses. There are several lesser known courses like chemical engineering, aeronautics, marine engineering etc which are preferable if you have interest in those fields.
I must also tell you that, getting admission into a good college of notable reputation is very much desirable because of the value it adds to your education. And, learning things & getting good knowledge on latest engineering topics are equally needed for a successful career. In this globalised era, proficiency over communicative english is a requisite.
Visiting sites like www.ted.com, www.howstuffworks.com, http://ocw.mit.edu/index.html can help a lot.