I'm using the FormTiddler/DataTiddler combo as well, but I'm not an
expert so please take this with a pinch of salt!
I've just done a test in my formtemplate, labelling one of the input
fields using CSS with a class (class="test2") e.g.
<select name=Type class="test2">
<option>please select</option>
</select>
and then put some rules for the class in my stylesheet
.test2 {font-weight:bold;color:[[ColorPalette::SecondaryLight]];}
I'm not sure if a class selector is the best thing to use for this
(rather than an ID selector or something more specific) but this would
depend on your particular usage!
warmest wishes, maki