In my opinion, some easy things to sketch are buildings, some cartoon characters like Mickey Mouse, cutlery like spoons, a car or even flowers. Te best thing to do is realize the shapes associated with what you want to draw which will make the sketches much easier to draw.
I agree with Aishu14 I also suggest that you go ahead and look up on the internet different websites which may provide free drawing instruction pages to print out or use directly on the web. Or you can also just look up stuff on the internet and try to draw them. Very easy to find simple drawings on the internet to try and draw. When you get comfortable then use your imagination and try and sketch things within your mind. The first thing that comes to mind just, start your media already on the page (pencil, pen, paint, Etc.) with that first thing. If you mess up DON'T erase (suggested by my very good sketching/drawing friends) just if you feel like you messed up just a bit too much to continue drawing what you wanted to draw then just look at what you started and in your mind think about what it looks like or what it looks like it could come out to be, Then start where you left off and incorporate what you started into the new picture in your mind.