1. I want to have my hair cut.
我想理发。
还能这样说：
I want a haircut.
I'd like to have a haircut.
谚语：
Desperate cuts must have desperate cures.
在非常场合采取非常手段。
2. Do my hairstyle like the one in the picture.
就按照图片上的这个发型给我剪吧。
还能这样说：
Please cut my hair like this in the picture.
Give me a haircut like the one in the picture.
应用解析：
do's and don'ts规则，准则。
例如：If you want to study well, here are some do's and don'ts.
如果你想学习好的话就照着这些规定做。
3. Leave the front as it is now.
前面的头发现在这样就可以了。
还能这样说：
Just don't cut the hair in the front.
The fringe of the hair is just OK.
应用解析：
be at the front 在前线;
bring to the front 使出名，使成为重要;
false front 假前发，装饰性的门面;假象，骗人的外表
4. I'd like to wear my hair in a bob.
我想留短发。
还能这样说：
I want to cut my hair short.
I want to have short hair.
应用解析：
Bob's your uncle.
不要紧，别着急;放心好了。