Ram,
With the correct preparation building your own house can be rewarding. It can also save you the overhead of a contractor, keep in mind I am a contractor.
The key word above is preparation and understanding all that is involved in building a house.
One, will your city allow you to act as a contractor?
Do you have a clear understanding of all the elements in building a house. at minimum you should get a form from your lending institution. This form will have every line item necessary to build a house. Once you fill this out and put all the prices together you will have a clear understanding of the cost.
Make sure you also have the time, this is a tough undertaking on a part time basis.
Acting as a contractor you will need to buy all the lights, plumbing fixtures and materials to build your house, this all takes a lot of time.
Another thing to take into consideration is warranty, just saying.
All in all with out experience your time would be best spent taking the time to vet 3 qualified contractors.
Once you have your plans and a list of plumbing fixtures and lights you can hold a job walk and talk to all three at once. The advantage to this is time and it shows the contractors you are looking for a competitive bid. also by having your appliance, lights and plumbing fixture needs in place this will give you a more accurate bid and not an allowance which will always be low.
At this time collect their references, then call the references. Ask if they communicate well, did the project come in on budget? is their work up to par, quality.
When your bids come in they should be pretty close in price. Then it comes down to references and personality. You will want to work with someone you are comfortable with.
If you have any questions don't hesitate to reach out and ask.