When I first started quilting I made sure I had an exact 1/4", but depending on the thread I used it wasn't coming out as a 1/4". The thread was a little heavy and therefore the blocks weren't pressing out to what I needed. In learning more as going along I found that using a finer thread and setting the machine needle to just a shy 1/4" was the way to go. Your points are not sewn into the seams etc. After awhile it will become automatic. My personnel preference for thread is aurifil 50wt. makes my piecing so much easier.
Good Luck
Suzy