Training for the steeple is about fitness first. Being a strong, tough runner must always take priority over having good barrier technique or working on special race tactics. Good cross-country runners are often good steeplers since they are generally fit and must be able to run in a slight to moderate state of anaerobic distress from the start and must respond well to interrupted rhythm.
Here are a few rudimentary things to do while getting a base in the off-season:
Hills are golden. Incorporate them throughout the pre-season. They don't even have to be deliberately used as hard work (occasionally they should be); just do them regularly.
Also regularly do hurdle drills and a few run-throughs over 1-2 hurdles. Some of these drills are standing or walking drills; these should normally be done after some of your faster-paced runs, so you are still a bit fatigued and must concentrate to execute them properly. There is no need to go into the standing/walking drills here; you can get standard hurdle drills from any hurdler or hurdle coach (the simplest ones include the walk-up to a fence stomp or wall stomp over a hurdle, "lead leg only" run-throughs at the side of a hurdle, repetitions of trail leg while standing next to a hurdle, "trail leg only" run-throughs, walk-throughs with hurdles crammed together). Just do the basic ones (and some run-throughs with full clearances) and spend most of your time developing fitness. Once proper technique is acquired, try to relax as much as possible during the drills and run-throughs, minimizing muscular tension and establishing the motions as second nature. You want barriers to be a normal part of your race, things you can literally take in stride or even use to your advantage in a tactical sense. They should not loom as imposing threats to be feared.
Include as one of the drills some dry run-throughs which work on water pit technique. The water jump is akin to running up a flight of about 10-15 stair steps in terms of the interruption in rhythm and the shift to anaerobic energy, and late in the race, this shift becomes exponentially noticeable, so having a smooth technique is helpful here so the early part of your race can stay less demanding. Start with a plyometrics box (shorter than barrier height) in the infield. Run up for about 30 meters and run past for about the same distance. Get in the habit of making a minor pace increase just prior to the barrier so you can get a good distance on your takeoff. Push forward more than up, but look ahead and not down. Your landing should be a quick (almost "rolling") one-two step so you can resume normal gait quickly. Jarring with either one foot or with both feet simultaneously is inefficient and tiring. Practice these details with the lower plyo box on a soft landing surface first so they will become easier to do over an actual water barrier (and you may slot into a technique that works better for you). You should usually lead with your strongest or most coordinated leg on the water jump, but practice pushing off with the other leg every so often - just in case.
During some of your normal easy runs in the off-season, get a regular track hurdle set to steeple barrier height and finish your run with a mile or two on the track, going over the hurdle each lap with a minor pace pickup for 15-20 meters before and after reaching the hurdle (you might progress to two hurdles per lap, then to four). This begins getting you acquainted with marshaling an effort to hurdle during a continuous (albeit slow) run. When your legs are ingrained to the slow pace of the easy run, you will have to call up a completely different set of mental commands to enlist the motor units necessary for hurdling, which is exactly the type of task you face in the middle and latter stages of a steeple race. Of course, you have anaerobic distress to deal with in a race, but the shift in concentration is what you are working on here. Your aim is to gain the ability to clear hurdles in a flowing, effortless manner, as though they are nothing more than part of normal running. Do not get in the lazy habit of clipping hurdles - while these practice ones may tip, actual steeple barriers almost never do, and you will probably eat the track if you fail a clearance, so try to get over cleanly every time.
Practice leading with both legs. If you can easily see a barrier 20 meters in advance, you can adjust your stride to lead with your best leg, but if the pack is tight in a race, you may not see the barriers 20 meters out, but will instead see the runners just ahead clearing them; you may then not have time to stutter-step and shift to your better lead leg.
For the regular season:
A staple session for the steeple is one involving reps (usually over five barriers per lap with no water jump, occasionally over four dry barriers and the water jump) of 2:30-3:00 in duration (usually 800m to 1,000m), starting at current (or presumed) race pace and progressing to goal race pace or faster by the final rep. Practice accelerating slightly going into and coming off of barriers. Run about 6 reps, resting about 70%-90% of the run duration between bouts, then tack on 4-6 x 170m accelerations in which you go over the water jump and another hurdle, working on accelerating throughout, especially coming out of the pit for that finishing drive.
Working at race pace and practicing clearing that final water pit and final dry barrier when shifting to kick mode are both invaluable in this event; do not neglect either. Make sure to get a thorough warmup, including a few run-throughs over a single hurdle, as this is always crucial when incorporating barriers into a session.
You may also run 3-4 x 400m (over five regular hurdles, no water jump) at about 8-10 seconds faster (per lap) than race pace, with 3 minutes of active recovery between reps, following with some standing/walking hurdle drills. This is a rather high-intensity session similar to one an 800m specialist might use (except with hurdles), but it is beneficial for the steeple, as this is an event which requires you to briefly process higher-than-normal amounts of lactate as a fuel (or buffer it) during the race and return to equilibrium quickly. For the sake of safety, use regular hurdles and no water jump on this faster work.
If you have never done an all-out 3,000m steeple, you might try a 2,000m race or a 2,000m-2,400m "dress rehearsal" time trial (including water jumps) prior to your first 3,000m race so you will get a feel for when (or how quickly) the pace becomes difficult. Start at your presumed 3,000m pace and see if you can pick it up (and by how much) in the last couple of laps. If your 2,000m steeple was all-out, your 3,000m pace will normally be about 2-3 seconds slower per 400m, depending on race pace. Owing to the varying configurations of steeple courses, accurate 400m splits are sometimes hard to get, but the 200m split during the first (non-water jump) portion of each lap can always be at hand (of course, it might be a tad faster than your overall pace including the water pit).
This is not that difficult - the steeple is just an endurance race, so focus primarily on becoming a good all-around runner with horse-like endurance. Become familiar with barriers and with race pace over those barriers (with bouts of about 800m or 1,000m during training), so you are comfortable and confident and know what to expect when the gun goes off. But there is no need to get too fancy by spending three hours per day working on special drills or searching for nonexistent magic steeple workouts, especially if it means neglecting fitness.