You've just opened a CV of a potential copywriter for your company. What is worth paying attention to? - Portfolio.
There should be at least a few samples in the copywriter's portfolio that have benefited customers. Ask him/her to share results in numbers: a number of views, comments, filled forms, etc.
- SEO skills.
Copywriters with knowledge of how to write SEO-copies can generate not only sales but also organic traffic to your website. Remember that one advertising copy pursues two goals at once:
1) making a sales pitch;
2) increasing your site positions on Google.
With no understanding of SEO basics, the writer will hardly achieve the second target which is crucial for your business growth. - Ability to conduct research.
An experienced copywriter has excellent research skills. To write a clever and deep article, a specialist needs to conduct thorough research of the topic assigned. Although each author, even an English teacher, can master the science of marketing and technical research, the time spent on this activity and research results may differ. Thus, always consider these two essential points:
1) the speed of the job;
2) the depth of issue studying. - Expertise in your industry.
A vivid example is a doctor of medical sciences who somehow prepared drafts about the diagnosis of a dangerous disease that are really useful for the audience. He can be forgiven for almost every writing mistake: lack of structure, poor text formatting, and even spelling and grammatical errors. Why? His text has enormous value for the target group. No person with a lack of expertise in medicine can share the same insights.
Thus, you need a copywriter who can dive deep into the topic he/she is competent at and produce expert-level texts. If you see in the portfolio works on the topics related to your business niche, you can easily evaluate the level of a candidate's expertise. If a specialist has never encountered the proposed issue but you decide to cooperate with him/her, you will run a big risk. - Literacy. Does it matter?
Among all the benefits of hiring a professional copywriter, you'll definitely mention literacy. However, is it a big deal that a text is perfectly written? In terms of common sense, yes. Text without mistakes is naturally correct and successful but you mistakenly think that it will generate a lot of sales.
It's just a psychological trick our brain is trapped in. We automatically equate a well-written text with a highly-effective one. Things look so in theory but the practice proves the opposite. The typos or the slightest mistakes do not reduce the effectiveness of the advertising copy, as you read in the case of a doctor of medical sciences.
It's much more important to take into account the content itself, how well it conveys the basic idea and whether it sells. Moreover, errors can even increase readers' confidence. While reading, you start perceiving the author as an average human similar to yourself. FYI:
a hard-skilled copywriter does not always write correctly in terms of grammar, this is not a strict requirement, especially today when we have numerous editing services like Grammarly.
Don't trust third-party services? Have the text checked by a professional editor (again, not an English teacher). That's how quickly and easily you can solve the grammar issue. Finding an educated and competent copywriter with a technical background is a much more difficult task.