Most disappointing logos are not the result of a bad designer. They come from a bad start: a short message saying "I need a logo for my business, something modern", followed by rounds of changes as the owner slowly works out what they actually wanted. That process is slow, frustrating and often ends with a logo nobody is fully happy with.
A design brief fixes this. It is a short document, usually one or two pages, that tells the designer who you are, who you serve and what the logo needs to do. You do not need any design knowledge to write one. You just need to answer the right questions honestly before work begins.