Giving is not a transactional thing. We should not expect something in return.
Don't post content to promote your services and products. People can see right through it. Post as yourself. As a human being trying to connect to other human beings. Create a (imaginative) conversation. When you advertise to people you push them away. They switch off. Advertising is all about you.
When you give something of value, when you help solve a problem, then people will listen. They then feel you expect nothing in return. People will start to engage. They will return to see what else there is. They will start to get to know you. They will start to like you. They will start to trust you. And that is the most important thing.
Don't have the mindset of not wanting to share your knowledge in fear of others copying you. In fear that you have to compete against them. Don't be the best kept secret. Then no-one will know about you!
Look at what chefs do. They share everything! They know anybody can cook! They put out recipes, publish books, present TV shows. They show you how to cook the perfect meal. They share this feeling of giving. They build their brand.
That is where the real power of building a community lies! By creating a mindset of giving.