This is the first and most important thing. To be able to sell something you have to have something right? So get started and be creative in all ways you can think of! Everything can turn out to be something cute that others might want to see on Etsy. Sketch and doodle, write little ideas down and keep them in a book of inspiration! Save pictures that you like and think about what you like yourself, what makes you happy and what you are good at. Not good at anything? Hey, c'mon now, of course you are good at something! I'm sure you are awesome at something even!
You can't expect yourself to be able to create awesome stuff at a boring desk in some gray sad corner right? That's just no fun! Try to find somewhere at home where you can set up a little studio for yourself. Somewhere to place all your supplies, sketches and sources of inspiration! I work at my kitchen table which is never ever used for anything else. I keep a bunch of inspirational images on my wall and all my supplies nearby so I can just reach out and grab something if I want to get started! This really helps, and c'mon, you deserve a cute spot all to yourself right?!
Now this might seem scary, but what's the worst thing that can happen? That nobody buys your stuff? Setting up an Etsy-account is easy, and after that you just go ahead and take really pretty pictures of the things you plan to sell. Good photographs are all important ok? Even with an ok camera you can take awesome pics, so just practice a bit and try different kinds of light and backdrops for your items. Read up about photo-editing. It's not very difficult to make a good picture look awesome with just minor adjustments.
Once you have your pictures, write cute descriptions of your items! I like to add little inspirational texts to my patches to add some sense of what I want them to make people feel. Dare to be personal and yourself. Speak with your own voice and don't be scared! People shop on Etsy to buy personal little handmade things that were made with love, not by machines and big companies!
You just keep on creating and wait for your first sales. It will probably take a while, but perhaps you are lucky and get your first sale the very day you open up your shop? You never ever know, but don't be sad if nobody buys your stuff in a while, it doesn't mean that your stuff isn't worth buying, it probably just means that the right customer hasn't found your store yet! Try to make your shop visible in various communities. Tell your friends, blog about it, write about it on facebook and don't forget to send some love to other shops too! I love that the Etsy community is so much about give and receive. Create treasuries with other sellers items! Make features about their items in your blog and tell them about it! Try to get your items onto sites like craftgawker or other peoples blogs. Advertising can be difficult and you never know if it will pay off or not, but spreading the word can take time, so keep your patience and just have fun creating new items while you wait.
You can't be a creative and happy person with loads of success unless you take care of yourself and have fun! Don't be scared, and believe in yourself! Making handmade things is soothing and creative. Don't force yourself and try not to stress yourself too much. Good luck, and I hope I have been able to help you in some way or another!