Improving Mazda5 2.0 Petrol MPG?

Just purchased a 2013 Mazda5 venture edition. I love the car. But I put £40 premium fuel in and I'm getting around 22/23MPG city driving. Got 3 bars fuel left and only done around 90 miles.

Any tips or opinions would help. Thanks!
2010 Mazda 5 Sport
Premium fuel isn't going to improve your mileage for this car.

Improving mileage is always the basics:

Good Air Pressure in the tires.
New air filter.
Reduce weight.
Drive like great grandma.

You can check out the guys who hunt for extreme MPG. They turn off their engine at every stop light and do a lot of shifting to neutral to coast, etc.