There are two methods I generally use to deepen my trance state. The first is to count backwards from a number like 10, 25, 50, or 100 as needed. If that doesn't do it for me then I will focus on physical relaxation for a while, starting with the feet and moving up to the top of my head. The reason for the relaxation is that an inability to go deeply enough into trance often for me is because of not having relaxed enough at the beginning. Something I have been meaning to try involves using a dial or digital display. You can visualize it and suggest that it start by indicating your current level of trance. Then adjust it to the depth that you are looking for. It might be helpful to have an indicator for where you are at and a separate indicator to control for where you would like to be. Then the process won't have to be rapid for you to see it starting to work. Instead you can watch the indicator of where you are at in your trance move closer to the indicator with your goal.