Do what Chewie says, plus don’t worry, wide stances like you describe are not wrong. Again, look at some PL videos. It all depends on your goals. Are you planing on competing in PL, OL, BB? It’ll change what you do to some extent. If you are training just to train, squat in the stance that feels best to you.
The video that Levelheaded posted a link too above is one of the best resources I’ve ever came across on the internet.
Also, I find that doing a few sets of overhead squats, even with just the bar, before any heavy lower body work has helped me hugely. Its got to the stage where my form goes to shit very quickly when I neglect doing them due to time restrictions or pure laziness/stupidity.
If you do decide to incorporate overheads, then go as deep as possible (I go absolutely ATG, deeper than my back squats). Don’t be afraid to sit at the bottom of each rep for a few seconds, and concentrate on pushing your knees out wide, before exploding back up.
They’re a fantastic exercise to incorporate in your warmups for increasing/restoring flexibility, learning to stay upright in the squat, and activating/strengthening the abs and lower back. Give them a try and let us know how you get on.