When you're working with cross-reality travel, your options are limited. Not many people know that other realities exist in the first place, and those people tend to leave well enough alone. So, for the amateur world-hopper, you've got four flavors of "bad idea" to pick from: Keystones, buses, jump points, and manual leaps.
Interreal objects tend to have some pretty funny properties. Keystones make use of these cosmic coincidences to attach a person's physical form to the other side of the reality gap. The effect is temporary. Letting go of the object will put you firmly back in your own reality, even if you do get a bit of a headache afterwards. Magic gloves and pendants are always in style— but these things are usually found, not made. And besides, jumping into someone else's reality for a few minutes is basically useless. Staying put is the goal, and that's what gets people in trouble.
The word is a little vague, but it basically means "vehicles." Everyone loves to recreate Back To The Future, after all. The devil is in the details— any vehicle that can travel from one reality to another is going to need to be very sturdy, very light, and very fast. Grabbing a DeLorean off the street isn't going to cut it. People usually find success with the most unexpected kinds of vehicles: Stone coffins, giant birds, or run-down elevators. Just cross your fingers that your bus doesn't miss its stop.
Here are two points between two realities that are somehow connected— in other words, a static wormhole. Stepping into these "cracks in reality" will definitely take you somewhere that you've never been before. You won't even explode on the way in. It's just a matter of figuring out where you are, figuring out if you can survive there, and figuring out if you're ever going to find a way to send yourself back home.
This is the only tried-and-true method, and the most dangerous one. It involves leaving everything in your own hands: The dimensional crossing, the navigation, the destination, the landing, everything. This method is how people end up catapulting themselves out of the known universe. As a safety measure, most interreality rituals are group efforts, overseen by at least five witches and performed in hermetically-sealed rooms under perfect conditions. It's a lot easier if there are witches waiting to catch you on the other side, too.
Sometimes, very rarely, individuals are born who somehow belong to two realities at the same time. These people are world-walkers. They have the ability to slide along the scale, hopping over to their other reality without any assistance or preparation. You would know if you were one of these individuals. It takes a lot of meddling from a lot of different forces to achieve the effect, and they're not the type to act quietly.
If you could find one of them, though, they could take you there. All you would have to do is hold their hand.