When you're doing a One Foot Manual, it's up to you whether you want to use your front foot to land on the nose or your front foot to land on the tail.
As soon as you pop your front foot back or forward, you're going to be directly over the back truck or the front truck, depending on which you prefer.
I generally like doing a One Footed Manual on my tail, so my foot would be right over the bolts. A little bit of the heel will on the tail. You want to find that perfect center.
Generally, it helps to keep your leg nice and stiff and straight so that way when you do lean back, you're not going to lean back too far. You'll have some nice control from your hips.
It's also very easy to fall forward or backwards on this one. If you're afraid of falling backwards, you want to maybe direct some energy towards the ground and not entirely backwards so when you do fall back, it will be a little bit more down than entirely back. You're less likely to get severely hurt or injured and hit your noggin.
So what you really want to do again, straight stiff leg, foot over the bolts. You're going to want to hop from the front to the back, so maybe even putting your foot on the ground in between instead of just a straight hop, would make it a little bit more easier to do this One Foot Manual.
Again, if you're having trouble with this trick, you might want to try putting your foot in a different spot on the board.
Each person has their own preferences when they do tricks and it's very easy to find your own groove as long as you're willing to try and find it.
Now remember, don't be afraid to try a Front Foot Nose Manual. They're not too difficult and they're not much harder than a One Footed Tail Manual.