If they haven´t played before, be sure to explain them all the rules so they don´t complain about something in the middle of the game (i had an experience where someone wanted his money back because he thought that QKA23 was a straight and lost lot of chips on that hand). If it´s a friendly home game i suggest that, but of course if it´s not then every player should know the rules.
In relation to the strategy as kraigus said it´s most likely that your friends will be just calling stations, specially if they hold a face card. The best way to take advantage of that is to just play good hands. I know that 6 handed you cannot wait forever for a premium hand, but try to avoid playing garbage. Remember that if they are calling stations you can´t
bluff, because they are going to call you anyway. Also remember that you won´t have any table image, so don´t try to take advantage of something you won´t have.
You can play just good hands as i said or maybe you can try limp in hope to hit a monster, because it´s most likely that there won´t be raises preflop.
Once you hit the monster or you already have a monster preflop, be ultra aggressive. Overbet, because they won´t understand the value of your bet and will call you anyway.
If you play in that way you won´t learn anything, it may be boring, and you shouldn´t play like that at any other table, but against those opponents that style is going to be profitable.
Now it could happen the opposite situation. They haven´t played before but maybe they read an article or asked someone else about some tips and now they just top 10 hands and fold to any bet if they don´t hit something. I think that it would be better for you if some of your opponents play like that, because they don´t understand that they´ll start playing 6 handed so they have to change their hand requirements. In that situation you just have to loosen up against those opponents, because they´ll fold to any bet if they don´t have premium hands, so they´ll become predictable.
In relation to prove that poker is a skill game, you have to remember that luck is a factor that counts specially for single events, so be prepared to accept any bad beat that could cost you the 1st place. The skill factor will be shown in the long run.