I did caricatures years ago. It was fun. I did em in the style of Nast ,(more detail and I made people look a bit sinister).
SOmetims I did portraits and I found the neatest thing for me was to maintain an "attitude" in my subject. Women are easy. Kids too. Men are tough because I see so many attitudes that can arise from facial tics .
Try doing old folks first, they are probably the easiest because everything is laid out foir you to see.
Look to do different kinds of support features (like tattoos, uniforms or some kind of weird hat and maybe even a snack or a drink).
I liked to use black and indigo or black and hookers backgrounds with highlights from behind (very freaky)
I used to project my subject onto a working sketch and then start mssing with the secondary stuff (here to put it and how lit hould it be). Then Id project the final onto the canvas board or wood (I never used stretch canvas for portraits)