So, because this is one of my pet peeves (especially if I'm behind you), but because I also realize that a lot of people apparently don't know this, here's my PSA:
The majority of intersections with stoplights (at least in my area), now have sensors in the pavement, and are programmed to change when a car is stopped at the light.
What does this mean? This means that if you are not positioned over the sensor, then in many cases, the light will not change, and you (and sometimes I) will be stuck at the light for-freakin'-ever.
So, don't pull too far up, don't hang too far back, and don't be so far to the left or the right that you're not actually in the lane anymore (which a lot of people do at the end of my street for some reason).
So how do you know where to stop? Well, in the center of your lane, at the white line. If you need more of a visual than that, you can usually see a faint (or not-so-faint, depending on how good the paving job was done) rectangle as you pull up to the interesection. Try to position your car directly over that. See photo below for reference.
So... now you know. And we can all act accordingly to reduce our wait time at stoplights. Thank you.