You should draw two things you see. Every day you should stop and stare at something or someone and find beauty or even offense in it. If you want to change it up every day then you could come up with themes each day. For example you could have a tall theme one day and only draw things that are tall, or make everything you draw tall. The key is to enjoy it.
I like the “draw yourself” idea that @Fiddle_Playing_Creole_Bastard had. That could be a fun project, trying to draw yourself a different way every day. Hell, I might try that.
I draw all the time for the kids, always have. Cartoon characters mainly. They do me the honour of hanging them in their bedrooms. Awww, melts with false modesty!! Basically draw whatever gives you pleasure or inspires you. It’ll show in the work you produce :¬)
Draw what challenges you. If you’re a detail oriented artist, try conveying your vision with a few simple lines. Or vise versa.
Or, take a subject that captures your attention and draw it from two different perspectives. Facing it on the same level and then climb a rooftop and draw the same.
Draw one of your favorite childhood toys, but in a different setting (space, inside a bag of groceries, etc) each drawing. Teddy bear on a trampoline one day, teddy bear inside a bag of Cheetos the next!
Mechanical drawings are always fun. Don’t worry about writing measurements, just pay attention to proportion and detail.
I started learning how to draw when I was 6 or 7 by tracing my dad’s engineering blueprints.
I had no idea they were plans for functional tools, I just thought their design was complex and interesting to look at in an artistic form.
My son drew dragons for a while. They super heroes. Then he got into more technical stuff having to do with shading. Right now he’s drawing fishing reels. He loves fishing.
My advice is to draw stuff from your hobbies and interests and loves. Otherwise the drawing will be too dry.