First, define why you want a web site.
Next define what you want it to accomplish.
You can display your interests, run a business, share your pictures, or almost anything else that gets your attention.
When the first two questions are answered, figure out what you are willing to spend to get the site up and running your way. Decide how much time you will spend on it, how much (if any) money you will spend on it, how much effort you will put into it, how much you will share control of it and how much advertising you will allow.
If you are comfortable with computer programming, start with HTML, add CSS and JasvaScript, and be prepared to keep on going. The 'net is changing all the time.
If you are more of a user who prefers to point and click, pick a graphic program that does the coding for you. Look over the other questions here for answers about editors. Learn at least the basics of HTML so you can fine tune a cut-and-paste goodie you find or troubleshoot your site when it misbehaves.
You will need a text or graphical editor for HTML and an FTP program to build and maintain your site. The choice of which one is intensely personal and is a whole question in itself. You will see several questions and answers on this subject here.
Now that you are ready to begin, grab a few sheets of paper. Draw a story board of the site. This is a quick sketch of what you will show your visitors when they come to your site. The idea is not to make art, but to keep your plan intact, despite distractions. Map out the paths from page to page. Put similar thoughts together and make separate pages for differing thoughts. Your home page should be a welcome mat, not the living room/dining room. Make the home page brief. Estimates of how long you have to get your reader's attention range from 6 seconds! for a business site to 30 seconds (sometimes more) for a hobby grade site.
Put down an idea of how to navigate from page to page. Do you want a custom interface or plain links? Your sites's style will be set in part by how a visitor navigates. Make the "controls" the same on every page so your visitor doesn't get lost or confused.
Keep a central theme for your site. Get advice on style, content, coding and graphics, but this is you, not a group of folk from the neigborhood, all talking at once.
The time/money budget you worked up before will give you most of the answers of whether to hire a web builder and a paid site or get free software, write it yourself, and put it on a free server. Which server depends a lot on the answer in your budget.
If you are going to "roll your own", make a couple of bookmark folders (favorites directories) for all the stuff you find as you search out the next hot item for your site. You won't be able to use everything you find as you go because you will find stuff for later. I have bookmark folders for Webmaster and for Graphics. A sample of the stuff in them is at the end of this answer.
I learned the core skills from HTML for Dummies Quick Reference and recommend it. Also check your local libray for books on HTML.
There are many other fine books and many, many resources on the 'net, like which not only have tutorials, but have software tools and references galore. The author of the site even recommends another book, despite being told not to buy one! I recommend any book for reference that is easy for you to use and has lots of wide margins. My book has little white space left, so it is very helpful!
The last point I will make now is don't forget to advertise. Put META tags in your homepage, at least, and submit your site to the busiest search engines. There's no other way anyone can tell everyone who will be interested about a new web site.
There will be bumps in the road, but if you don't panic, it will turn out well.