Everyone goes through that beginning stage where it is easy to forget things and make simple mistakes, even though you are enthusiastic about scuba diving. Learning is always easier if you have been put with a diver who is more experienced. Knowing little things that only experience can teach you are valuable in underwater safety. It is a good practice to make all of the safety checks, routinely, at the correct moments. Whatever you need for a dive, make sure that it is in the boat, before you get in. You will need things from the dive shop, so get in the habit of checking everything before leaving the store. Your scuba gear should fit, so make sure it does before leaving the rental store.