>>I quess that the editors who review the applications are rather bias. Can anyone share some tips on how to write a good application ?
There is certainly a bias in favor of Standard English grammar, spelling, and syntax. (This snippet is 0 for 3.) I didn't see your application; so it may have been done more carefully.
We review, classify, and describe websites. In my opinion, we do more, and do a better job of it, than any other general web directory. We're looking for more people who can do this honestly and well. Your self-description and your three website descriptions are all we have to judge you.
1) Demonstrate a facility in Standard English. This is a practical, not a moral, judgment. Nonstandard English (or other World language) makes the directory look unprofessional and seem unreliable. Some people aren't willing to take the trouble (or perhaps aren't able) to do this part of the editing task. We don't generally accept their work in the user-visible portion of the ODP. (But anyone at all can submit sites, and an editor will do the, um, editorial work on the description.)
2) Demonstrate a grasp of the ODP taxonomy. Find sites that match the category.
3) Demonstrate an understanding of the public benefit, and a willingness to do volunteer work for it. We know you have interests both personal and financial; so do we all. Be candid about them; show that you can temporarily set them aside for the common effort. (This isn't so strange -- you're already offering to give time, energy, and attention -- all of which you could have invested toward your own immediate benefit. And there are, in exchange, real benefits to having accomplished -- and being seen to have accomplished -- something this useful.)
4) A lot of people use the self-description to promise what they will do. A better recommendation is to describe what you have done. For instance, if you done 'pro bono' work building websites and and maintaining relevant link pages, cite the page! You're demonstrating a history of volunteer work including experience in reviewing and describing websites; you're also showing a knowledge of relevant websites that could benefit the directory. There's no set "perfect application," though: just remember that we're looking for people that have relevant skills and character, and give us evidence.
5) You may trust that personal information on your application will be kept confidential. The editing community does not see these applications; only ODP staff and meta-editors see these applications. You can, for instance, give a primary e-mail address, even though you plan to use a throwaway e-mail address for all communications related to editing. Nothing on your application (except your "editor ID") will automatically appear in your public profile, or even to other editors. Many editors, for various good reasons, prefer to work anonymously; we will respect that. But it is better to give accurate information in your application, and that will not prevent you from editing as anonymously as you wish.