I want to learn how to Determine the complexity o fthe algorithm.

I want to learn how to Determine the complexity of the algorithms but don't know from where to start? I read DS a little bit but dont know anything about determining the complexity of the Algos. Can someone here guide me to learn that.

What about Cormen's famous book "Introduction to Algorithms". It's good starting point. IMHO.
Is it what did you want?
It would be better if you could post you algorithm here.

Thanks Oleg for you reply.

Well I am not looking for finding the complexity of some specific algorithm. What I am aiming at to become able to determine the complexity of algorithms.

The same book Oleg mentioned will tell you to understand complexity of some well known algorithms and also any algorithm in general. But I personally feel that the book is not very beginner type.
Usually space complexity is given less importance these days due to availability of large main memory sizes, virtual memory,etc.
For time complexity,there are two widely used methods, the simple method based on guessing the overall complexity when its known for small input size and the master method based on predefined formulas.
There a nice introductory explanation here .

Hope this helps