Optimising Code?

[Naif]

Hey guys, first post *waves* I've been into programming for a number of years; no formal training and only console-based C++, but ever-curious as I am I'm always looking to expand my knowledge. I've recently moved into Visual Basic .NET and have put together a booking system -type app as one of my first test projects, however given my lack of experience in event-driven languages I was wondering whether someone might be willing to take a look and point out anywhere I'm going wrong? Not sure what the protocols are around here in terms of reviewing code, don't want to post it without clarifying first, but hopefully it can help some people (myself included) pick up some new skills =]