The cheapest form of transport to neighbouring Island is by ferry. From the ferry, take a songthaew or share a van to your hotel in Samui, they are a lot cheaper than the taxi's.
Take care of your personal belongings! Always take valuables with you and don't leave them unattended in your luggage! You'll be prompted to leave your bags in special area, so take care
The cafe on the pier wins most pissed-off and miserable staff award! These guys make it look like they're deigning to do you a huge favor when they get off facebook to make you a coffee!