Every company wants only the best and certainly when it comes to advertising where a lot of budget is usually used, working with the right copywriter is very important.
Firstly, it is important that you are clear of what you are looking for. Familiarise yourself with the different websites catered to translation and copywriting services and start your search from there. Ask clearly regarding the services they offer and ask them questions to get all your enquiries answered.
Secondly, asking for samples can be a good way to gauge the skills and competency of the copywriters. Usually several samples are presented and this would give companies the flexibility to choose which sample suits them best.
Thirdly, understanding and confirming the budget is also important. As copywriting is generally slightly more complex than just translation in general, it would be good for both parties to understand and agree to a specific amount that would work for both parties.
These are some of the steps you can take before engaging with a copywriter to assist you with your ad copy. Do you have any additional pointers?