Find web hosting Drupal is not available as a precanned service like the blogger.com or wordpress.com blogging engines. To use Drupal you must arrange for your own web hosting, and install Drupal. This is fairly simple but it does take some bits of work. I have a list of web hosting providers to help you find hosting arrangements.
Install Drupal Largely Drupal installation requires downloading the tarball, unpacking it, setting up a database, and running the install wizard.
Enable blog modules Once Drupal is installed there are a few modules to enable. The blog module is not enabled by default.
Enable comments Blogs generally involve letting the public make comments, and this needs to be enabled.
Comment permissions Your comfort level of allowing comments turns into permissions settings.
Install CAPTCHA modules The CAPTCHA modules do an excellent job of preventing SPAM comments.
Set up vocabularies Vocabularies in Drupal are like "tags" in social bookmarking sites like del.icio.us. They connect postings by topical similarity. The simpler blogging engines (wordpress or blogger etc) only connect postings by the date of posting. Using vocabularies to connect postings by topic can help your search engine ranking, and can help your readers find topically oriented articles.
Configure contact form The contact form is optional and allows readers an easy way to contact you by email. The contact does not publish an email address on the site but instead is a web form that when submitted sends an email.
There are several optional modules which may be useful and desirable.
Install and enable Feedburner module (optional) You may or may not like Feedburner's service, and this module integrates the Feedburner service with Druapl.
Install and enable Feed Buttons module (optional) This module presents "buttons" that help people subscribe to the site feed.
Install adsense or amazon module (optional) There are several modules to facilitate making money.
Install editing assistance modules -- bbcode, BUEditor, fckeditor, etc (optional) The default Drupal text editing experience is pretty blah. There are several add-on editors which improve the editing experience.
Install image upload & attachment modules (optional) It's helpful to add images to your blog postings, and these modules facilitate doing so.
Install Google Analytics support (optional) Google's Analytics service helps you see traffic statistics for your site. It's an excellent service and this module integrates it with your site.
Install XML Sitemap support (optional) The XML Sitemap is a service which notifies search engines you've posted new content, and helps the search engines know when to trawl your site to see what's new.
Install pathauto module (optional) The pathauto module is highly important for search engine optimization as it makes your site use friendly URL's which do good things in the search engines.