Ear piercings are okay. Tattoos? It depends on what, where, and what colors. If it's a lightly colored little flower, butterfly, star, etc. that's somewhere not visible, i.e., feet, back of the shoulder, etc., that's okay. Tramp stamps or dark colors and sleeve tattoos? No.
Piercings should be kept to the ears and not too many. I've always hated nose piercings and never found out why a girl would think it's cute or something...I mean, you have to pick your nose to take it in and out haha, yeah that's hot...
Tattoos are fine at a minimum in my opinion. It'd be best to keep them in places where they wouldn't be seen all the time, but I don't mind one on the ankle or even the side of the stomach, under the arm.
It's hard to generalize an answer for this because everyone has different taste and everyone looks different like some people can pull things off and others just look stupid. Beauty is in the eye of the beholder. Me personally I think piercings are cute on a girl and some girls can pull off gauges which is pretty hot, tattoos can be anywhere I don't have a preferance with them but I think its really cool if they have a meaning or if the design is unique. Hope this helps