This is what I would do. Google "Venetian mask" and go to images and you will have lots of ideas to look off of. When it comes to making your mask, first you will need a cast of a face. If you don't have one then take some tin foil and press it against your face. Be sure to make it thick and strong enough so that it won't collapse. Now to the mask making itself. I always use paper mache or paper pulp or a combination of both. I use 1 part flour and 1 part water with newspaper for the paper mache and I add a little bit of salt to the goop so that it dosen't get mold in it. A good trick is to always rip the paper and never cut it. This blends the pieces together and gives it a smoother finish. Dip the paper in the flour water mix and start to layer it on the cast of your face. My rule is after it dries, hold it up to a light and if you can see light through it, add more layers. This will make a nice strong mask. After it is completly dry, sand it down so that it is level and smooth then you are ready to paint. I always use either acrylic paint or spray paint. A "cheat" that I have is if the mask is still lumpy after you sand it, use textured paint when you paint it. This hides imperfections really well. After the paint is dry, you will want to seal it so that water can't get into it and make it floppy. Hope this helps.