So nothing works huh? You have tried everything ?
There are some techniques and websites that you will find everywhere which are listed for domain selling. You would have done everything above, but you have not found any success. There can be many reasons.
There is a smart way to produce results. Try to find a role-model or someone that is selling the domains consistently. Try to model him, do what he does and take help. You will learn new tips and tricks from them and may suddenly make your first sale!.
While its tough to find role-models it doesnt hurt to ask in community forums or PM active members. People may answer if you ask right questions . Persistence is the key here. Try to find ways to help others so that you can be mutually benefitial to each other, that way you increase your chances of finding a role-model.