Alignment: What are the checkpoints?

I've been getting the correct distance, but lately its been going left a lot! Samle with my driver...sometimes sliced.... sometimes straight. What are the checkpoints to absolutely be sure the alignment is correct? Thanks!

Make sure your feet, hips and shoulders are parallel to your target line. It's easy to just check that your feet is square and forget about hips and shoulders. When your practising, practice with a club parallel to your target line and when you take your address, take a second club and lay it across your shoulders/hips and check that they are square.

I totally agree with Can Putt... I was aligning everything except my shoulders which were about 5 inches closed. This throws everything off because the tendency is to square the club head at address but when you come down to the ball it will open again. Notice that when I moved my shoulder to the right alignment position the club head followed without purposely moving it. Only then everything is aligned - feet, hips, shoulders, and clubhead. Now the club head in the downswing follows a natural path to the ball, nice and square.