One of the most common obfuscation techniques is basically to obfuscate the names of the classes, methods, variables, fields, and so on—basically everything that has a name. Obfuscation can get even harder if you obfuscate the names into other alphabets or other symbols (since the names are in Unicode), such as Chinese or Japanese.
You can easily deobfuscate such samples by running the de4dot deobfuscator from the command line, like so:
de4dot.exe <sample>
This will rename all the obfuscated names, as you can see in the following screenshot (the HammerDuke sample is shown here):
You can also rename the methods manually to add more meaningful names by right-clicking on the method and then selecting Edit Method or clicking Alt + Enter and changing the name of the method. After that, you need to save the module and reload it for the changes...