Toddler Eatting Habits

Have hit the terrible tow's in every way including refusing to eat.  My terror will only eat crackers, bread (most of the time), museli bars, kumera and sometimes potato.  I make sandwiches with meat, egg etc.  All of a sudden my fruit and vege eating girl will not eat any.  Anyone got any tricks to convince them to eat?  Or do we just go with it.  If she doesn't eat her dinner I don't offer anything else (I feel terrible) and leave her dinner there until she goes to bed.  I have fruit on table for her to nibbler on and we eat fruit to encourage her to eat as well.  Any suggestions greatly appreciated.