If you're going to bother putting in training hours to improve your shot before the fall rolls around, you may as well create as authentic a scenario as possible. You'll thank yourself later when the buck or bull of your dreams comes strolling into view and you've built the muscle memory to shoot from whatever position is necessary.
In this video, I walk through how to use your tripod to train your shots from a variety of heights and stances. If you nail down these various kneeling and standing positions, you immediately expand your opportunities for success when opportunity presents itself.
Perhaps you plan on carrying your tripod in the field for your optics and can throw a small sandbag in your pack to convert it into a rest. If that's the case, then this exercise is even more realistic. If you plan on relying on timber and rocks alone, then you'll be one step closer to a successful shot if you already have your stances dialed in.