Just don't overdo it. Be yourself. If the two of you are a good match, she will stick around. If you weren't meant to be, she will move on.
Telling her she looks nice is very generic. It is better to say something more specific (yes, the comment about her earrings would be nice) but don't do this on a daily basis because it starts to sound insincere.
Don't buy her chocolates on a regular basis, although every now and then is nice - just to let her know you were thinking about her.
ALWAYS give encouragement, but be careful about advice. Lots of girls don't really want advice about their problems - they just want to vent. It might be a good idea to say "do you want to know my opinion, or do you just want to talk about it?"
Relax... I'll need some information first. Just the basic facts - can you show me where it hurts?