Check the promise
Read your main headline without the logo. Could a competitor use it unchanged? If so, it may describe the category rather than your offer. Try explaining who the work is for, what problem it addresses and what makes your approach relevant. Specificity gives creative work something to work with.
Keep the journey consistent
The advertisement makes a promise. The landing page should explain it. The enquiry or checkout should make acting on it straightforward. When each stage is created in isolation, the visitor has to connect the dots. Write the central message once, then adapt its depth to each stage.
Decide what counts as progress
An impression, a visit, an enquiry and a qualified sales conversation are different events. Agree which one the campaign is designed to influence and what happens after it. Otherwise a marketing report can look encouraging while the sales team sees little useful change.
Make room for learning
Test a clear hypothesis, such as whether a particular audience responds to a particular use case. Keep the creative, destination and measurement connected. If several things change at once, a better result may still leave you unsure what to repeat.
The practical check
Before launch, ask a person unfamiliar with the campaign to explain the offer and the next step. Watch where they hesitate. Fixing that hesitation may be more useful than producing another variation of the same ad.