Shortcuts

Tabs

Next tab / previous tab: ctrl+tab, ctrl+shift+tab
New tab: ctrl+t
Close tab: ctrl+w
Duplicate tab: alt+d ('go to the navbar'), then alt+enter

Navigation

Back (previous page) / Forward (next page): alt + left and alt + right

Extensions

Stylish

IIRC Andy made heavy use of this.
You can use a single custom script to switch between a night-mode and a day-mode, similar to how Dark Mode (the extension) works.

Here's the script I use:

/* Taken from the Dark Mode extension, Dark Mode #18 (grey dark) */
html {background: rgb(51,51,51) !important}

html * {
  color: rgb(144,144,144) !important;
  border-color: rgb(57,57,57) !important;
  background-color: rgb(39,39,39) !important;
}

a, a * {color: rgb(97,129,169) !important}
img[src]:hover, input[type=image]:hover {opacity: 0.4}
input, select, button, textarea {background: rgb(74,74,74) !important}
a:visited, a:visited *, a:active, a:active * {color: rgb(82,95,102) !important}

input[type=radio] {
  border-width: 0 !important;
  background: none !important;
}

/* The stuff below was added by me, Nathan Wailes */
img {
 	opacity: 0.4 !important;   
}
img:hover {
 	opacity: 0.5 !important;   
}
img:active {
 	opacity: 0.6 !important;   
}

/* Twitter */
tcu-imageWrapper[style], tcu-imageWrapper[style]:hover, tcu-imageWrapper[style]:active {
    opacity: 0.4 !important;  
}

Misc

How to speed up browsing / reduce bandwidth-usage

Disable images.
Disable scripts.

How to separate work and non-work browsing

It's embarrassing if you're using the same computer for work and non-work activities, and you have to share your screen to show something to your coworkers, and they see some search you did for butt cream or Pokemon or something.
To avoid this, create a separate Chrome "Person" (Click on the person image in the top-right and click "Manage people"), and move all of your work-related bookmarks in there, and don't have them in your "personal" Person account. And then just have separate desktops for work and non-work. I use a totally-different image for the work account's Person (I use the alien) so that it's easy for me to see which I'm account I'm using.