Gustav The habit, in one sentence: know your numbers and move money on a regular cadence, invoice the moment work is done, and never let cash flow run on guesswork.
Why it matters
Profit is an opinion; cash is a fact. You can be "doing well" on paper and still be unable to pay a bill this week because the money you earned is stuck in an unsent invoice or a client who pays in sixty days. Most small businesses that fail were not unprofitable, they ran out of cash at the wrong moment. The rhythm of money in and money out matters more than the total.
And you cannot steer what you do not look at. A business you understand financially is one you can make calm decisions in. A business whose numbers you avoid is one that surprises you, always at the worst time.
What it looked like for me
There have been stretches where the work was there but the billing was thin, because projects were not quite finished and invoices were not quite sent. Nothing was wrong with the business, the money was simply not moving on a rhythm. The fix was unglamorous: send the invoice the day the work is delivered, keep the records current, and actually look at what is outstanding instead of hoping it sorts itself out. Money you have earned but not invoiced is not income, it is a favour you are doing the client.
How to build the habit
Pick a weekly money check, fifteen minutes, same day every week: what came in, what is outstanding, what is due. Invoice immediately on delivery, not "when I get around to it". Track who owes you and chase it without apology. Set aside tax and VAT the moment you are paid so it is never a nasty surprise. And always have a rough idea of your runway, how many months you could cover if the work paused.
The pitfall to avoid
The classic trap is avoidance, doing the work brilliantly and then never quite getting round to the boring admin of billing and bookkeeping. It feels harmless and it quietly starves the business. The other trap is spending against money that has not landed yet; treat unpaid invoices as hopes, not cash. Tighten the rhythm and a lot of money stress simply disappears.