1.
Starting with the obvious - Avoid printing where possible. Use email for mailing. Also start using Office OneNote which can store documents in a way that makes them easy to find. You can even search for text in images.
2.
Choose the draft option - Most printers have a draft print copy or quick print option. The quality will not be as good but the print is perfectly readable and uses less ink.
3.
Laser Printers - Laser printers have come a lot in price and although still more expensive in general than an inkjet, the cost per page of printing is less than inkjets.
4.
Refill your ink cartridges - This is an option to look into. It can be a lot cheaper to have them refilled.
5.
Print Manager - For larger organisations and schools it is well worth looking into print management software that can track and restrict printing in an organisation. Huge savings can be made. You can limit printing by group, by colour etc.