Hi Makbog, First you have to choose your niche (topic for blog)...it should be of your interest otherwise you will loose focus after some time. Then check what is already available on internet regarding your topic. Then evaluate how you can add value through your blog/website Once you complete the above steps that means you are ready to start blogging...... Buy a Domain name....then hosting plan Then install the word press (most of the hoting website provide it free of cost) Now its time to choose your theme (go to wordpress.org and select any theme which you find suitable for your content and format). After installing your WP first follow some steps to make it secure (you will find a lot of article on internet about it) Then start writing article and publish your post... Once your blog have enough content then publish it to search engines and then continue good work.....
If you want to implement a new functionality on the website, check if there is a Wordpress plugin already created to solve that issue. Probably there is.
You don't need to pay for domain name and hosting [you can if you want of course], you can use free services for wordpress like wordpress.com or blogger.com!
It all depends on what kind of blog you want to make, do you want affiliate blog? ad blog? sales blog? or subscriber blog? Answer these and I will be able to help you
See, below URL. You will find there great tips design website in wordpress http://codex.wordpress.org/Site_Design_and_Layout