You'll have to be pretty nimble-minded to execute most of these short term mnemonic techniques, but making the effort makes you so. It is to your advantage to become familiar with the methods. We're reaching beyond mere short term mental tricks.
The following is a time-honored Zen approach to raising the level of consciousness:
Go over, in your mind, the precise events of the last twenty-four hours. Get as much detail as you can. Whenever you sit down, having done a cycle of action such as going shopping, a board meeting or whatever, again, go over the sequence of events in precise detail, paying attention to all the sensory modalities. You will find that you get better and better at doing this, and that as a result you stay more fully conscious in the here-and-now.