It's important that you don't view the dive guide/master as a substitute for having to take personal responsibility for the dive. Ensure that you apply the skills and procedures that you learnt on your Open Water course.
The best mindset is to plan and conduct any 'supervised' dive as if you were unsupervised. If nothing else, it ensures that you remain safe in the unlikely event that you got separated from the guide, or if the guide displayed less professionalism than you might expect.
The 'pros' to using a guide (in the proper way) are that you (should) have access to some expert knowledge about the dive sites you will be visiting. The guide should understand the best route/s to navigate the sites and should be able to show you the most interesting features of those sites. They should also have a very high standard of personal diving ability, meaning that you should not have to worry about them having problems - thus eliminating any stress that may have arised from having to dive with another novice diver. Lastly, the dive guide should have exemplary rescue skills. Whilst this is highly unlikely to be an issue, it is reassuring to know that should there be a problem, you are in safe hands.
Golden Rules:
1) Do not abdicate responsibility for your dive to anyone.
2) You are responsible for your own safety. Make decisions accordingly. Do not be tempted into doing so-called 'trust me' dives... where you are diving to the guide's limits, not your own.
3) Fully apply the lessons and skills you learned on your Open Water course. Use every dive as a means to polish your skills and improve your diving ability.
4) Plan and conduct every dive whilst considering the contingency that you may have to complete it alone.
5) Never assume that your diveguide/master knows best. If in doubt, apply what you learned on your Open Water course.
6) Remember that "
any diver can abort any dive, at any time", don't let peer pressure from other divers or dive professionals force you into doing things you are personally uncomfortable with. Stay within your comfort zone and be prepared to say 'no'.
7) Be realistic about your skills and capabilities. Don't let
over-confidence drag you into situations beyond your scope of reaction. Be aware that '
you don't know what you don't know'. There's a lot of knowledge which isn't taught at Open Water level, so there are many risks that you will not be aware of yet. Consequently, do respect the recommendations that have been given by your training agency, especially those about depth and time. Dive conservatively and accept that agency/industry recommendations originate from genuine safety concerns.
8) Be realistic about your skills and capabilities. Don't let
under-confidence cause unecessary stress. If you dive conservatively, within the limitations of your training and experience, then there is a high degree of safety. Your Open Water course provided you with all the skills and knowledge necessary to be safe providing that you stay within those boundaries and apply what you have learned.
9) Open Water diving is an especially safe pursuit. If you follow the rules and recommendations...and apply your skills and knowledge, then there is
very little to go wrong. The only real thing that can cause an accident or injury is
panic. Panic is very bad, because it will prevent you from reacting effectively and appropriately to even a small issue. Panic can lead to 'instinctive' reactions...especially to rush to the surface. Instinctive reactions can hurt you. If nothing else....do not panic underwater. Learn how to recognise, respond to and overcome the sensation of panic. If you can control panic, no matter what goes wrong, then your safety is virtually guaranteed. There is virtually nothing that can harm you underwater, except yourself.
10) Enjoy. Enjoy. Enjoy. Don't expect personal perfection. Don't stress about things. Just relax and enjoy what you are doing.