Field translation works randomly
The module used for translating fields (title, help text, description, allowed values) is i18n_field.

Internationalization 1.8 shipped with a broken i18n_field module, so in many cases nothing would get translated.

The first issue that fixed most of the failures was
[7.x-1.8 regression] Field translation fails in numerous situations
It has now been committed and is a part of the latest -dev release.

Contrib field types such as commerce_price might need the following patch:
Extend support for contrib field types

With those patches applied I had no problem with translating any part of a field.
For translating allowed values (radio or select fields), my process was this:
1) Go to manage fields, click edit next to my list(text) field.
2) Click the Translate tab on the next page. 
3) In the table, find my language and click "translate".
4) I can translate the values under the "Field settings" vertical tab.

Also keep in mind that when showing one of those values on a rendered entity, you need to use the "Default translated" formatter (set under "Manage Display").