How Do I Secure My App?

I’m looking for good information about ways to
1. Use a licence key or the like.
2. Ways to prevent (or at least to make it hard) to install it on other computers with the same code.
3. Make it usable for only a specific amount of days (i.e. 30 days). (also, possible ways, if they exist, to not use system clock, such as an internet clock with and without the need to be connected after entering the code)
4. How to hide this information, if possible also from installation tracking programs.