Overall, no harder or easier than any other occupation. If you focus on the keys to success, planning, marketing and financial management, you can be successful owning your own business. If you find you are not self-motivated, willing to put in 100%, or significantly distracted from the rest of your life, it can be harder to be an entrepreneur.
The answer is actually how hard you make it for yourself. Take an inventory of your skills or interests. Then do some research to see if anyone is in need of those skills or interests. Decide what your time is worth to you and see if the prospect is willing to pay you.There are a lot of Market Research tools available to you that can help you in your search. Yahoo has plenty of them for you to use.
Not hard if you are an originator. Otherwise extremely difficult and requires a whole palette of human skills.