hi cyril,
are you using tabs in your admin view? If not, do it :) With tabs you can organize your admin interface and make it more user friendly. For example my last two tabs are always ... | meta options | publishing options.
I also recommend you to create your own admin template, for example based on the default one. Why? Because you can give your admin interface a better style. Example: background-color for your groupx-fields :)
regards
pixelneco