One thing - after all the tramming/leveling of the bed, extruder calibration, proper slicing... If you're having trouble with getting prints to stick, nine times out of ten, it's because the hot end is not close enough to the bed.
I use a glass plate over my aluminum bed, and clean it with denatured alcohol every three to four prints, but I use no hair spray or glue stick, and get excellent 'squish'. The best manual method I've found for getting good bed adhesion, or 'squish' is to use the bed leveling gcode of your choice, but to use a standard 18 pound piece of paper, and when getting that 'scratch' (compression of the paper between the bed and the hot end), make sure the 'scratch' is more than just a little, but not too much to rip the paper - just shy of ripping the paper is what works best for me.
Be sure to read the doc that I had shared above for tramming your bed, squaring the gantry, replacing the bed springs, and tightening the eccentric nuts. This will all help to get a more pleasant 3D printing experience.
Here's a link on extruder calibration...