startx

Start i3 with dbus so notifications and other things work correctly by using this as your last .xinitrc line:
exec dbus-launch --exit-with-session /bin/i3

tips

disable capslock

Or swap it with control or something.

mouse acceleration

Mouse acceleration is awful... Unless you're using a trackpad.

display notification from cron

Also from ssh and other non-display TTYs.

disable screen blanking

xset s off -dpms

useful software

xev - Print contents of x events
xprop - Print properties for x
xrandr - Monitor information for x
xwininfo - Window information utility for x
xsetroot - Set simple color wallpapers in x
maim - screenshot tool
feh - simple image viewer, can also set a background
grabc - Grab a color
ueberzug - Draw images in a terminal