pick a right day...for example, birthday....bring her to a nice restaurant...with harbour sea view or night view...have a nice dinner...
after that...walk with her nearby the harbour...
tell her how u feel with her...being with her...just tell your feeling...
since it's you...don't have to prepare...maybe just some roses...
remember to bring a jacket...cos u might need it...and then cross the harbour by ferry
bug her in heart