After you have done a good onpage optimization, the offensive in the offpage area follows. This area is definitely more demanding and takes more time.
In contrast to Onpage search engine optimization, this is actually only one thing and that is backlinks and promotion! So offpage optimization is about link building, but how can this be promoted?
For example by:
Content, link exchange, guest articles, forums, social media, directory entries
Content / guest articles / Directory entries
Wherever possible, you should publish great content that readers recommend and link themselves.
Free option: http://artikelverzeichnisonline.de/
If you also use online directories or classified ads portals, register anywhere.
Simply ask manufacturers, suppliers or partners whether they are interested in a link or banner exchange.
Find specific forums in which you surf or which topics are relevant. Register and enter your company / service & URL in the signature. Post diligently and even have some fun, you create a backlink with every post. However, you shouldn't give senseless answers or create threads.
Thanks to Facebook, Twitter & Co. you also have the opportunity to leave your mark there. Which is why it is advisable to actively participate on every platform.
Of course, this area can also be advertised further, but with the beginning of this, let's call it basic building blocks, you are on the right track.