There are a few key tips in getting a unity down, other than just learn a royale. If you can royale on the boot with ease, unities should take you an hour or two to get down to a reasonable level. Anyway, the first thing you want to do is make sure you land in unity position. Approach the object like you are going to royale it, and jump into the air.
Lock in your strong royale foot solid on the object, and throw the other foot behind. Technically you should do both at the same time, but while you are learning its ok to stagger it a bit. Just like in miszous where the back foot will naturally lock in, the same is true with unities- your back foot will just glide on if your front is in proper position.
Foot position is also crucial. Before you even try these, stand still on the ground cross-legged so that you can get a feel for the proper stance. Your feet should be at least a foot apart when you land. This is harder than it sounds, because most people tend to jump on very erect with their feet literally touching each other. You need to squat down just like in a royale and make sure you are grinding on the boot. While grinding in this position you have to keep your feet very firm and locked in, other wise you will end up sitting cross legged on the object.
There isn't much else to it, other than going out and getting hurt trying it... There are a few problem solving tips that I can give to help speed things along, though. Most people tend to grind too much on top of the object, thus riding up it and having to step out on top of the planter. To solve this, just remember to keep your weight back just like in a royale. If you are jumping on and immediately locking up, then you are not landing in the proper position. Remember to put that royale foot on and use it as the main foot. The back foot is on just like a guide. Also make sure to squat down nice and low so that you are on both skates' boots.
This grind is a technical one, but it is not very difficult to learn. I go for a week or 2 without doing them and pick them up in 15 minutes again. So just concentrate and think of it just like a royale. One final note-- You should be facing at the object just like in frontside. If you face down the rail like a soul (and like you will want to do), then it looks ugly. The same goes for standing up straight like a board. Shred it up!
