Before you go off sniping, you will need to bind keys that are comfortable to you. Here are the binds taht are most useful for sniping; I also assigned them to keys that may be comfortable:

Key/Bind Description
bind "SPACE" "+attack" Shooting/Attacking Key
bind "CTRL" "+attack2" Special Key/Zoom
bind "MOUSE1" "+forward" Move Forward
bind "MOUSE2" "+back" Move Backwards
bind "MOUSE3" "+duck" Duck
bind "SHIFT" "+duck" Duck (for non wheel mouse)
bind "ALT" "+jump" Jump
bind "," "+moveleft" Strafe Left
bind "." "+moveright" Strafe Right
bind "ENTER" "+speed" Walk Slower
bind "k" "+gren1" Primary Grenade
bind "c" "+use" Use Key
bind "u" "messagemode2" Team Talk
bind "y" "messagemode" Talk
bind "b" "saveme" Call for a Medic
bind "v" "discard" Discard Ammo - good if you're emped
bind "n" "sniper_zoom_in" Zoom In (See Chapter 6)
bind "m" "sniper_zoom_out" Zoom out (See Chapter 6)
bind ";" "duckon" Duck Toggle (See Chapter 6)
bind "'" "duckoff" Duck Toggle (See Chapter 6)