I suggest you 1st do some html cources.
visit this page:
http://www.w3schools.com/html/html_intro.asp
Just walk through the whole cource, and then start experiment yourself with some things, After you done the cource you will be able to make small and easy websites, after that just try some things, make a nice layout etc. the most important thing to get good at it is: Practise and trying.