It is not so easy to promote a group on social networks. If earlier it was enough just to publish interesting content, now the competition has become incredibly strong, and the old ways have lost their relevance.
Direct ways
Collaborate with administrators of other groups. Write in private messages a request to arrange an exchange of information. Let's say you advertise for a while about a third-party group, and its administrator - about yours. However, the owners of promoted groups are unlikely to want to arrange an equivalent exchange with beginners. In this case, you can offer to post a post for a day in exchange for a few hours, or buy out ads.
There are even special exchanges that offer such a sale. The largest of these is Sociate. Here you can find offers for advertising on any site. Let's say you need to promote a culinary group in Odnoklassniki. Just add some ads and pay for the placement. The better it is compiled, the more participants you can get.
Organize contests in your group. The more valuable the prizes are, the more people will want to participate in the competition. Standard conditions are some kind of prize and an offer to repost. The winner is determined randomly using a special program. Just be absolutely honest, make a video showing exactly who is winning the prize. This will build user confidence.
You can also order a professional group promotion. This concept should not be confused with wrapping. In the first case, you will be led interested visitors who will be happy to read your content, and in the second, only bots that will bring absolutely no benefit.
There are even whole companies that are engaged in similar activities, but you can also find private contractors. To search, it is better to use all the same forums and freelance exchanges.
Indirect methods
Publish as much content as possible. The more often users see your posts, the more activity there will be in the group. Accordingly, there will be more new participants as well. But don't forget about the quality of the materials. The information should be really interesting, useful and necessary. Also, do not publish texts alone. Upload videos, make photo collages, arrange polls, etc.
Order a unique group design. This applies not only to the avatar, but the menu and other elements. For example, you can create a character that will be displayed on all posts (for example, a deer in the "Overheard" group network). The required performer can be found on the forums or freelance exchanges. Just place an order or choose a ready-made offer.