Hydrate is important!
Being in the water sometimes distracts us of hydration, so it is important that when going to the pool, bring a bottle of water to leave at the side so that you can take a sip while swimming. Hydration helps improve stamina and condition.
Have breakfast before swimming.
Many people who swims do it in the early hours, before having breakfast. It is important to have a light meal or breakfast before swimming in the morning as you're coming from an extended period of inactivity and swimming will demand a significant energy expenditure. It is recommended to have a fruit about 20 minutes before, or to have a balanced breakfast at least half hour before.