Get the chemistry going on. A good threesome requires the chemistry among the three persons. They have to be sexually attracted to each other, no matter it is a FFM, MMF, FFF, or MMM threesome hookup. Therefore, before having a threesome dating, have a casual dating first. Get to know each other. Go to a movie or a dinner. Talk to each other to get the chemistry going on. If one of you doesn't feel attraction to another, maybe you should get a change. If you are a couple, change a third. There are lots of tinder for threesome apps out there. Just get another match. If you are a single, use the same way. I am sure it won't be hard to find another perfect match for you. A good preparation can ensure a wonderful threesome.
Boundaries should be set beforehand. Different people have different comfort zones and boundaries. Before jumping into the pool, you should bring up your boundaries. Be honest with yourself and each other. It may be sensitive, but don't hold anything back, or you will face some awkwardness during the process. The more open and honest you are, the better threesome experience you will get.
Try to stay as sober as possible. I know that many people may feel nervous in their first threesome hookup. It is absolutely okay to feel nervous. Actually, everyone will face different degrees of stress in their first threesome. Many people would choose to use some alcohol to boost their confidence. That is cool, but do not drink too much. No one wants to sleep with a drunker. Besides, you need to stay sober to get everything in the right place, right? Sometimes, you can't remember the boundaries after you are too drunk. It may lead to a failed threesome and a bad memory.
Here are a few tips I would like to offer you. I hope they can be useful.