Practice! Other recommendation are use good lube, warm your toys up, relax and learn to control your breathing/muscles and patients.
Are you having a depth issue or a girth issue?
Glyph is a pretty long toy, while very well tapered it might be either getting caught before sliping into the bend or your anatomy might be causing it to "bottom out."
If its a girth issue get a thicker toy. I have found that training for knots with knots is sub optimal. Since you pop a knot in, its not really stretching you out consistantly. This doesnt apply to all knoted toys though, Xar is an example of a fantastic trainer, as well as being a amazing toy. A toy I used for warming up for quite some time was Clayton. Its reasonably thick with a great taper and the texture make things interesting.
You could also look at ika, tako or Winstons tail for a more dedicated trainer/stretcher. These are a nice combo toy for both depth and girth training.
If you want more serious trainers check out SquarPeg toys. They have an amazing selection of high quality products. My personal fav is Slink.
I am happy to answer more question.