# English translation:
Asking for 50% upfront is already a good start, but you need to structure the project milestones better. It's not just about money, it's about getting everything properly documented. Make a simple contract (it can even be by email, something short) where you specify exactly what will be delivered in each phase and when. Something like: "Phase 1 - Concept and sketches (50% paid upon hiring), Phase 2 - Finalized design (remaining 50%)". That way the client knows there's a commitment and you have proof that you discussed it.
Beyond the upfront payment, since you're worried about wasting time, start charging a cancellation fee if the work gets interrupted on their end. Like, you've already spent hours on the project, that has a cost. If they insist they can't pay the rest, at least you charge by the hour for work already done. A lot of people are afraid of seeming difficult, but it's not difficult, it's professional. A client who disappears without notice? That's what's actually difficult.
One thing: never start working before you see the money from the first half in your account. Wait to confirm it actually arrived, not just their promise. And as you grow (and you will grow if you do this), you can start requiring 100% upfront or use platforms that guarantee payment. But while you're starting out, these basic rules cut out 90% of the problems.