The attitude of reducing demands on resources like electricity and gas is paramount amongst these. To this can be added, the saving of paper in offices and homes.
Reusing of materials can help the environment because it then reduces the need for producing material for use. So reuse your plastic bags, newspapers where possible and think of any possibilities of reuse before you consign anything to scrap. There are a lot of organizations, which offer to do this, even if you do not find any way of reusing your old and obsolete items. This is especially true of electronic goods.