I struggle with this and have guides and feet and tape too. Watching the needle is a big no-no, but I find myself doing it all the time.
There is a ruler that works well -- you tape it on to the machine and it sort of makes you look at the line the material should be on before it hits the presser foot, but it is hard to keep it down on the bed of the machine.
I would like to be an officer of the club since this plagues me DAILY!!