When writing descriptions for a job board post, it is important to try and think like a potential employee. You have to highlight the things that are important to them, while avoiding language and requirements which might cause the right person to completely skip over your ad. Emphasizing benefits and challenges, while using positive, proactive language, can help to attract a larger number of applicants, giving you more options to choose from so that you can find the perfect employee.
It is also important to avoid things that might shrink the talent pool and limit the number of applicants. Avoid language that is targeted at a specific group and instead use neutral wording that will have equal appeal to everyone. You should also hold off on listing too many requirements or prerequisites, as skills can often be learned on the job, and setting too high a bar will make people less likely to apply for the position.