Rename "-none-" option for select list field type
Implement hook_form_alter() or hook_form_FORM_ID_alter() and use the following code:

$form['field_name'][LANGUAGE_NONE]['#options']['_none'] = t('Select');


example:

function MODULE_form_FORM_ID_alter(&amp;$form, &amp;$form_state, $form_id) {
    $form['field_name'][LANGUAGE_NONE]['#options']['_none'] = t('Select');
}


The t() function is for translation.  It may not be required, but it is good practice to use instead of hard-coded strings.

To remove - None - as a choice all together, you could unset the key using hook_form_alter as well.

example:

function MODULE_form_FORM_ID_alter(&amp;$form, &amp;$form_state, $form_id) {
    unset($form['field_name'][LANGUAGE_NONE]['#options']['_none']);
}


If you're not using it already, be sure to install the Devel module so you have access to the dpm() and dd() functions.  They are incredibly valuable when playing with Drupal forms.