If you want to end up with a surplus, it's a step that can't be skipped. Knowledge is power, so they say, and the way to gain knowledge about your family and money is to write down every penny spent by any family member for three months. No fancy budget formulas, no guilt. Just write it down. This step is difficult simply because of its tedium and because it's not the way it's always been done.
Difficulty levels can increase with more family members spending money.
A first entry in the spending log might be tiny spiral-bound notebooks and pens for each spender. The proper tools can help, but without agreement among the responsible members of the family, notebooks won't get you very far. In each couple, there's usually one who spearheads each change. Maybe you are the one who wants more financial stability, maybe it's your partner. A minimum of agreement has to exist before living below your means is a possibility.