Trying to call a variable from another script in C#

I have been able to do this successfully with Unityscript by declaring

 var instanceName : ScriptName; 

and then by using instanceName.variable

but I haven’t had any luck in trying to accomplish the same thing in C#.

Any one able to help me with this?
Thanks

make sure you put ‘public’ before the declaration, eg

public ScriptName instanceName;