The mosty obvious key to good content is that it is ORIGINAL. Google and other search engines absolutely love nice, clear, informative and fairly long original content. They try to find this every second of every day.
You need to have a title that grabs people's attention. Ideally, this title is placed in front of them just where and when they need help with something, help that you provide in that content. The title needs to get that accross. 80% of people will read a title only, 20% will read the rest of it if the title is good. The title therefore plays a very important part.
What do people use Google and other search engines for? Answer: to find out the answer to a question!
Your content needs to identify the problems faced by your prospective audience and then give them the solution. They should be keen to read it and then keen to use your solution afterwards. This will build up trust and trust leads to further engagement and a relationship.