The next two unlocks for the Sniper are very rifle-specific: the Gruber 5 Stabilizer and the DysTek Hi-Scope x4. The DysTek Hi-Scope x4 does not take an active slot on your customizable build sheet, and will be with you anytime you dial up one of the three sniper rifles in the game. Once you are zoomed in with a right-click of your mouse, roll the mouse wheel forward for two more steps of zoom than what you previously had.
We've previously recommended that Commanders take the Engineer role, but the Sniper class is also a wise choice. Commanders who can take a high perch with a x4 scoped rifle can spot enemies and call down orders and supplies much more quickly than through the top-down menu. This is especially effective if the enemy is in a concentrated front and is enveloped and/or contained.