I want to know how to start investing in share market and which is the best option now?

As I see it, there are 2 parts to your question

1. How to start investing & what are the best options

Like in everything else in life, it pays to start slow, spend time in learning the ropes, test the waters and only when one becomes confident, dive in deeper!

So its actually great that you can invest in small amounts only. You could start with as low as Rs.500. I would recommend that you start with the mutual fund route, investing Rs. 500 every month or two months, or as feasible. Now which mutual funds to start with? Obviously the very best- those with long track records with high safety, funds that take low risks and deliver high/above average results. How do I identify such funds? Fortunately there is a very good place that keeps you updated. See and learn more about the Top-rated funds at http://www.valueresearchonline.com/toprated.asp

Consider also this other answer that has pointers to how best to make your money work best for you -using the principle of compounding returns. That also has some specific fund allocation suggestions for different risk profiles. http://in.answers.yahoo.com/question/index;_ylt=Al9dU9682KNAZsBqqz.Pn9SQHQx.;_ylv=3?qid=20080604231439AAM8Nnq&show=7#profile-info-7vo1JiYIaa

And now the second part of your question
2. Techniques/Strategies for investing and getting aware of the share market and investing basics

a. Since you are starting out, first you need to familiarise yourself with the basics. Consider the set of excellent articles at sites such as these below
Great investing basics websites
http://beginnersinvest.about.com/
http://www.investopedia.com/articles/basics/
http://www.kiplinger.com/moneybasics/

b. Next, I would recommend you to first get solid grounding in Investing. 3 must read books. If you haven't heard of these, buy them NOW, today. They will be your invaluable guides to safe & prosperous investing and future wealth creation.
1. Intelligent Investor -Benjamin Graham
Considered the bible of all investors, this will foremost teach you the basics and most importantly, how not to lose money. Thats the first lesson you need, believe me
2. One up on Wall Street -Peter Lynch
This is another classic. Tells you how to spot winners from what you see around you. successful products, companies. Practically shows you how you do not need to be a hot shot financial analyst to be able to spot good moneymaking opportunities in stocks
3. Common stocks Uncommon Profits- Phil Fisher
As you dabble for 1 or 2 years, make some money and also make some small (hopefully) mistakes, you will start itching to catch the multi-baggers, the ones that go up 4x-10x in a couple of years! This book show you how to sift out probable winners

c. Next, you need to understand more on the promising sectors, promising companies, etc. So start reading the Economic Times daily, watch CNBC TV 18 -your stocks with Udyan, UtVi, NDTV Profit. There are also dedicated shows on Sat/Sunday mornings 9.30 am onwards till 11 am or so on CNBC TV18 - that cover investing basics, markets next week-basically trading calls for the week, and other useful shows.

d. You could also join some investing/Trading groups to learn more from other investors. Here by listening on the conversations, you can shorten your learning curve. I dont do Trading so I cant tell you about such groups, but there are good long term investing groups like http://in.groups.yahoo.com/group/lawarrenbuffet
You can check out more such yahoogroups at http://in.dir.groups.yahoo.com/dir/Business___Finance/Investments/Online_Investing_and_Trading

e. Once you have spent some time in all above, say 3-6 months, you will see that you start forming some ideas of your own. That you are able to comment on or question what someone is saying on TV, the yahoogroup or even what your friends offer as stock ideas. If you are unable to comment /question anything on most of the pronouncements by analysts/others thats a pretty good indicator that you are not ready yet. If you venture out at this stage, you are probably not investing but gambling away hard earned money:-)

So read up, ask questions, see that you are able to interpret/question/comment on what others are saying. Only then take small bets in companies you believe in, which have some track records. Don't go for quick profits, thats a sure recipe for disaster!

Good Luck!