We see several etching techniques used here, with cross hatching for the shoulders, and then straight, lighter lines for the facial features. Light comes in from our right, leaving dark shadows onto the left hand side. This use of lighting helps to increase contrast within the piece, making each feature stand out a little more, when etching already lacks the variety of palette that you might find within Rembrandt's paintings. You will find a number of related etchings from his career, where he produced self portraits at a relatively young age - see Self Portrait in a Cap, Wide-Eyed and Open-Mouthed and Self Portrait with a Broad Nose for example. Rembrandt took advice from a number of etchers early in his career in order to best understand this new medium that he had not used before. Even by this stage, he was already shows signs of mastery.
Research, even just by us, was needed in order to find any great information on this artwork, as it is not amongst his most famous self portraits. The original Dutch title of Zelfportret, Luisterend, naar Voren geleund beared more success, and we immediately discovered that the piece can be found at the Rijksprentenkabinet, which is the Rijksmuseum's prints and drawings department, that was officially created in 1799. This is hardly surprising, of course, because their collection features a great number of prints and etchings from this artist's career but it is important to be sure about its location before you are able to learn anything more. Typically, we can then likely find more information on the etching and its prints from articles and books published by this institution since the department there was set up, more than two centuries ago.
Peter Paul Rubens was an artist that Rembrandt greatily admired and he would look to this master for inspiration around his own self portraits. You will actually find a good amount of similarity within their careers, at least from the perspective of content and themes. They were, of course, stylistically and technically both very unique and it would be wrong to say that Rembrandt was anything other than a true genius who took inspiration but incorporated it into his own world. Rubens himself actually liked to put himself into group artworks, almost as something of a surprise to the viewer, in a similar way to how Diego Velazquez would appear in Las Meninas, for example. Rubens himself can be seen in Self Portrait in a Circle of Friends from Mantua and Self Portrait with Brother Philipp Justus Lipsius and another Scholar.