Beginners often avoid people because they are considered too difficult. I once read in an art book ‘don’t paint people, paint carrots’ (wish I could remember which book – if you are the author send me a mail and I will attribute it to you). This was a great piece of advice. The heads should only be a 7th/8th of the size of the body – don’t make your heads too large (if they are too small you can always make them bigger!)
On this example of a couple walking notice the jacket shape of the man; notice also that the left leg is very pale; you want to give the impression of movement. Notice on the women I have only painted one leg and I have continued the colour of her skirt into the leg. Avoid using too many colours (there are only 2 colours used here). Notice the feet tail off to nothing – this also gives the impression of movement. In my opinion addition of figures gives the painting some life. A painting without figures makes for a bleaker, lonelier landscape – of course this mood may be what you are after.