In 3-5 years time you really can't imagine what house prices will be. It's a great goal, home ownership, and I'm sure you'll get there if that's what you really want.
Deposits should be more than 10% - especially post GFC. The barefoot investor said about 3 weeks ago that for a $300k house you need about $85k for deposit stamp duty and fees. That's a lot.
You will need a very very good history with credit ratings and a good relationship with a bank in order to get a house with such tight margins.
As for saving tips - there are loads out there. But firstly, before you start looking for ways to save - you need to know what you are spending. If you don't know exactly where the money is going, you will never know what you can save on.