Hi Amit, i have a blog based on wordpress and i want to design my own theme instead of using a freely available theme which looks similar to other blogs. Is it possible if i have knowledge of HTML and no other programming language expertise? Are there are easy tutorials or wizard kind of options for me? – Ravi from New Delhi

Ravi, wordpress blogging CMS is used by millions of bloggers online and first of all i would recommend you to use available free wordpress themes. Previously i tried out many wordpress themes offered by different bloggers for free and i kept trying and testing them for some hours in order to get feedback from my visitors, because the design should not make us feel happy but should make our visitors feel happy and help them to easily navigate through our blogs.
LaunchPad , Custom Vs Free Wordpress Themes & Christmas Wordpress Themes

If you are not really happy with the available themes then you can start developing your own with some basic php knowledge but since you said you are having no knowledge on programming nor designing then we can go with the following option :

Using Wordpress Theme Generator Online – This option is for people who want to generate a very simple blog theme with the help of a wizard along with some small changes and download the whole theme in a very easy format. The advantage of using this option is that you can design your own theme based on your requirement. You can select the width of the theme ranging from 100% width which means fluid to fixed sizes of 750px, 950px & 984px. You can decide what kind of sidebars you would feature on your blog and select them from the drop down options available.

These generated themes are very much recommended because they are very light in size and load super quick on any browsers and on slower broadband connections. You can even do a website speed test once you active these new design and see if your blog loads more faster in this new design.