Wwe go to play parties sometimes, though Wwe tend to avoid co-ed parties for a variety of reasons, mostly cuz it's hard for me to get solidly into subspace with men's voices around me and because my Mistress, being petite and female feels a little less Dom-ly with a bunch of big guys around. Wwe like our women-only events. But Wwe've been to a few co-ed parties at private houses of folks Wwe were comfortable with. Your profile says you are ftm and most women-only events i've attended specify that you have to live day to day as a female but the lines are always pretty blurry and definitions change from group to group and some women's events are women + trans men so you might check into the women's events in your area, if any, and see what their rules are. There aren't very many lesbian events, but when there are, many of those include trans men. It just depends on the group or host.
For the most part, leather guys, in my experience, are some of the sweetest and least threatening men i've ever met, even the Doms. i find that most people at play parties and other leather events are very friendly and approachable but also very respectful. The general rule is not to touch anything or anyone who doesn't belong to you without permission or invitation. i don't know if that will help you. The big club in Oour area that hosts most of the parties has mixers or coffee socials before most of the parties to encourage socialization, mingling and negotiations before the actual parties so you can arrive at the party with a play date already arranged or at least knowing a few people who are going to be there. If the organization hosting the event has something like this, you might be able to go to that and then, knowing some folks might make you more comfortable. If they don't have a pre-party mixer/social/thing, maybe just a munch or two, hopefully you'd meet some of the people who circulate in the community and logic holds that at least one or two might be going to the party. You could specify that you are looking for people to buddy up with (and/or negotiate play with if you want) for the party when you introduce yourself at the munch. Or, how are you finding out about the party? If it's through Fetlife or a message board or online group of some kind, maybe you could post on the message board or Fetlife group that you are looking for some friends/contacts (and/or play partners) for the party. If all else fails, you could contact the promoter/host/whatever s of the party and ask them to put you in touch with someone who might be a good contact point so you don't feel so alone in a sea of strangers. You might also just try making some friends in the leather world and seeing if you can find someone you feel comfy with who hosts private parties in their home. There's options. It's also totally legit and kosher to go to a party and not play at all. Maybe for a first try, just set the goal to go, mingle, be a voyeur and soak in all the sexy sights and sounds, and then call it a night.
Overall though, i think parties are great. i love the atmosphere and the energy of good play party. i highly recommend it if you can find a situation that you're comfortable with.