Hi Hi And stuff!
So um yeah, Hi and stuff.
I have taken interest in Hammer for portal two and I'm plotting a little aftergame story.
I am in need of a couple of things.
1: A voice actor for some custom Glados lines
2: A voice actor for the villain. (Well more of an annoyance really)
3: A play tester who knows Hammer inside and out. who can help fix bugs if any.
4: Some Subscribers on my youtube channel xD
Also is there a healthy and detailed tutorial on doing a boss battle?
I've seen a couple custom maps with that kind of element in it.
I don't know how long it'll be before I release the set of maps or how long it'll take me to get really good at portal 2 mapping. But I have theroughly enjoyed both games so yeah.
Well hello there!
Welcome to thinkingwithportals.com!
Generally when you're requesting help from people it's good to show off some previous work.
If you've got something fancy and interesting people are more likely to help than when you don't have any skills you can show. So I would try and show some of your work, before requesting people to help.
Playtesters are generally less hard to get by, but if you need proper advice and good hammer knowledge help showing your skills first might be useful too. For example, as long as you're not using scripts I could probably help, if you are using them all over the place you better ask someone else. It really depends on what you need who can help.
Subscribers to your youtube channel are generally generated by creating interesting content. And to advertise it you can always put a link to your youtube channel into your signature 
As for boss battles; it really depends on what you are planning to do. If you do stuff that's similar to what's done before ask the authors how they did it. If you want to try something completely new, try and try until you get it to work the way you want it. For example; the boss battle in Aperture Valentine started off as a simple concept, and it took me 91 iterations to get it to work the way it does right now.
Asking for a tutorial on a boss battle is about the same as asking for a tutorial how to make good puzzles. There are some things that might really help, but at the end of the day you'll have to make your boss the way you want it to be.
ill HELP 
i finally found someone to help thank god!!! Jeez people dont want to help me just cuz i dont have any of my projects posted. WATS UP WITH THAT!!! lol whatever but ill play test for u and subscribe to your youtube channel. Add me on steam. ill help you with instances and create custom textures for you
alsoo you can help me on my new project im making too sorry idk if i could cut for a villian voice actor cuz im sorta shy with my voice but whatever i hope this is going to be great!!!
This is pretty much the combined knowledge of this forum. Just create a topic and hopefully your problem could be sorted.
I'm willing to do some voice acting, my voice is bass-baritone with a Midwestern American accent.