Starting the downswing

My bad shots and card ruiners tend to go low and left, this can cause a whole heap of trouble when it happens. Anyway i have been reading (never a good thing) that it could be because i am not starting the downswing with my hips, and it seems therefore getting the clubface to the ball ahead(?) of my body with the face shut, therefore low and left. I do not really think about starting the downswing though, so to eradicate this completely, what should i think, to start the downswing or how should i initiate the downswing?

I bump my left hip, seeing as I'm right handed, slightly towards the target and that triggers me to start unwinding. You have to be careful because you could start to slide your hips too far to the left and then you've got a whole host of problems.

Timely thread. My game's been pretty poor recently until a practice over lunch last week when I went back to one of my old swing thoughts which was to solely concentrate on initiating the downswing by a slight move of my right knee inwards towards my left side (as a right-hander). Made an instant difference to my game to the extent I shot a 68 round our place on Friday and I didn't miss a single fairway with my driver, something that has been unimaginable so far this season. As Grumpster says, when I do this, everything else simply follows and seems to be completely in sync.
My one weak shot when I'm thinking this on the downswing is to maintain my height as, occasionally, I drop my right shoulder and chunk it somewhat.

Genuinely don't think about it at the time. Just whatever is natural at the point I feel like I have run out of backswing. No swing thoughts if possible!

If they go big and accurate I guess I must be. If I'm right/catastrophically right I think I might be too arm-y with little hip movement and if I'm disaster left it's all my right shoulder and arm feeling a little left out and trying to get in on the act (or I over compensate for OOB right).

With wedges however, I often time whatever transition there is with an idiotic instinctive dip with my knees which I think is a sub-conscious act to take some pace/distance off the shot. Cue fats, unmentionables, thins and some very disasterous scores from just 50 yds shy of the green where I should be converting the chances (2 instances of the identical error on our 4th on Sat and Sun this week, unmentionable into mangoes and the end of a -1 promising start both times).

i sometimes do the knee dip Roller. i generally put it down to never and bring a bit "yippy". maybe its me trying to compensate sub consciously for a poor start to the swing