Tip from a experienced sculptor, stop detailing!
What you need to do is take a second, third and even fourth look at your sculpt. Its impressive what you have accomplished so far, so here a few pointers.
- Your vents are sticking out, if you look at the picture, they are more inwards then outwards.
- The back of your helmet is to curved. It helps to build your sculpt up in blocks. This way you curve them down later.
- Try to keep using templates, try to use pieces of plastic or other straight objects for thing like the box behinde the visor. This way you know for sure its straight and flat.
- Try a rolling pin for pieces of clay you are putting on. This saves alot of time flatting the clay out.
I dont know they hardness of your clay but its seems to me that you are using a clay that is way to hard for this type of sculp. Your Clay should be firm and not to soft. If you are using clay that can only be modeled when hot (cant find the English term) you are absolutely F*****. Its impossible to work with unless your are building a car model larger then 30cm.
BUT your sculp doest look really promising, I will keep a eye out