First thing, it helps a LOT playing with a team. Even playing with another person who can help you lane (if playing carry) can help a gigantic amount if they know how to support.
Secondly, expect to see at least one of either Drow Ranger, Riki or Sniper insta-picked each game in the really low skill games. They're very popular amongst the lowest levels because they're easy - rightclick them to death, move on. All are very easy to gank early on.