[pgeorgi]

To start simple, make sure you don't spend more than you earn (excluding exceptional circumstances). A simple table, GNU cash or even pen + paper are enough for that: record every transaction you make, no matter what tools you use, as long as it's reasonably low-friction.

I used a simple table with columns date, account, value, purpose. "account" helps getting a sum total for each bank account and for cash, to check how my table compares with reality (ie. bank statements and the content of my wallet).

Simply by tracking money flow you already learn a lot about your habits, while collecting data that helps you optimize it if necessary. I also found that making spending a conscious matter like that already reduced impulse buys.

After that, the other ideas are good ones - and you'll know if they're achievable for you and how.