Track your spending. It's insane how obvious that might sound, but having all your outgoings over a month laid out in front of you can make it really clear where there might be savings to be made. I used to pick up a pack of biltong and an energy drink before work every weekday - it was only £3 every morning. However, that's £63 a month right there.
Other than that; see if you can change your routine or mindset in some way to allow savings. I've started waking up earlier so I can walk to work, and not being so anxious to get home early so I can enjoy the walk home a bit more - I'm lucky to live within three miles from my office, and to be able-bodied (and have the area be walkable etc.) but it saves me about £150 a month on train tickets, at the cost of walking about 2 hours a day.