So I've been trying to work on my abs without going to the gym (because no time). I've been getting sick of planks and I hate crunches with a passion, so I followed some 
advice and got an ab wheel.
The moment I saw some videos on how to use it, I'm like, "I'm gonna faceplant so hard when I try this". So when it arrived, I tested it and sure enough, faceplant. Obviously, my abs aren't strong enough to keep me up, so more strength and practice in that area would definitely help. But is there anything I can do in the meantime to get there? Some kind of half-rep or something to help me build up my core? Or should I just go back to planks and reverse crunches?
I'm sure you probably are, but you're doing it from your knees, right? Don't try from your feet for your first go.
Aside from strengthening your abs (planks and reverse crunches are good, if you have a pull-up bar, I'd recommend some hanging leg raises too), you should get your triceps and other pushing muscles ready to hold you up. Push-ups are great here. If you have access to TRX straps, fallouts would also be great to do. Nice thing about TRX is that you can change up the difficulty by changing how far away your feet are from where your strap originates.
Part of it is just getting the balance and everything too, which is just practice and occasionally perhaps biffing it. That's where some quasi half reps would come into play. Keep your butt on your heels, start with the wheel at your knees under your shoulders, body already mostly parallel with the floor, then just rollout with your arms, keeping most of your body on your legs and get used to keeping balance with minimal weight on your shoudlers/arms.
It's definitely worth doing ab roller, but you are right that it doesn't really have an easy mode.
Thanks for the advice! It's all very helpful!
I am indeed doing in on my knees, aside from once or twice on my feet to see what it's like. Good call on the hanging leg raises, too. I've been using my pull-up bar quite a bit for my arms, so I'll just add the core to it as well. It's only been a day since I got the wheel so you're right that getting the balance is a huge part of it haha. I'll definitely keep your form advice in mind when I practice.
If you get on your knees, and face a wall, you can do "partial reps" by just going to the wall.
I'd start off doing a couple sets of a couple reps and gradually move away from the wall over the course of a couple weeks (maybe measure or put some tape down to mark where your knees should go).
A standard double progression would be something like 3x5-8. Everytime you're able to get up to 3x8 at a given distance from the wall, you move back a bit more and start at 3x5 the next session.
Edit: be warned to go easy as you start out. Ab wheel DOMs are excruciating.
Gotcha, that sounds like really good progression. I'll probably start somewhere nice and slow just so I can build up to something I'm comfortable with. Plus, that'll give me an incentive to stick with the routine of it.
Oh yeah you're totally right haha. Tbh I only went with the wheel because I was getting a little bored. I'll mainly focus on the usual routines like squats and planks and add in the other stuff for flavor.
Most ab workouts are honestly nonsense. I got a decently defined six pack and external obliques just by doing compound calisthenics exercises and being at a low body fat percentage. I've never done an ab specific workout.
An ab wheel is designed for anti extension exercises, so I'd recommend looking at that, and easier variations of them that can incorporate an ab wheel. But train your abs in the same way you'd train any other muscle. Some 50 rep ab endurance workout far from muscular failure is going to do nothing to make your ab muscles more defined or stronger, that's just going to work endurance.
