Web pages are typically filled with numerous links, menus, and widgets that are intended to make it easy to find what you want. However, these become distracting when actually reading content online. Further, many websites appear to ignore guidelines for readability. Fortunately, there are ways to improve your own experience when reading.
Improve the look and feel of Wikipedia
Despite being such a useful and popular resource, the desktop version of Wikipedia comes off as being poorly designed and hard to read. The font is small, the lines are too long, and I seldom, if ever, use the menu bars at the top, left, and bottom of the page.
Wikiwand solves Wikipedia’s problems. Wikiwand is an extension for Chrome, Firefox, and Safari that serves up Wikipedia’s content, but with a much nicer interface. Compare…


Note the big reduction in clutter, improved font face and size, and the addition of a sidebar to help navigate the page. With the default Wikipedia, you have to scroll to the start of the page to see the table of contents.
Improve many other pages
Improving the look of non-Wikipedia pages requires a different approach. By far the most popular extension (at least for Chrome) is Readability. However, at the time of writing, the extension does not save your preferences. For me (and, judging by the reviews, many others), this won’t do.
Just Read is an excellent choice for Chrome users. As its name implies, this extension strips all the clutter and lets you just read the content. Here’s part of the same page shown above, but after Just Read’s conversion

You can easily tweak the appearance of Just Read by adapting the default-styles.css file. (No css knowledge required.) For example, I changed the default font simply by finding the appropriately named attribute and changing as desired.
body { font-family: 'Merriweather', serif; line-height: 1.75em; font-size: 16px; }
Advice for non-Chrome users
There aren’t extensions for Safari or Firefox that I would specifically recommend as I don’t use these browsers. However, there are bound to be a number of options a quick google search away.