Stamina training.
When you want to swim some distance you need to work with your stamina. It’s like cardio workout.
In the beginning start your swim with good warm up and stretching. It should take you around 10minutes. Prepare yourself and your body for work. You’ll avoid shock and decrease possibility for injury. You can warm yourself up on the pool bank or in the water. Whatever you comfortable with.
Then, choose your distance, in the beginning start with 20-40lenghts. Then you’ll be able to go for 80+lenghts.
Next, up to your distance, set your pace up. Little bit stronger cor shorter distances. Between 50-75% of your max swim. Then… go for it! First quarter you should go quite easy and at the end of you distance you shoul feel tired not shuttered.
In the end do a cool down and stretch yourself out. It should tane aprox. 5-7minutes. Don’t forget to take fluids during and after your training!
Remember that during your swim you should focus on your stroke. Keep it right. Pick one element and focus on that- arm pull, balance, hand entry into a water, etc. There are a lots of things to improve!
At least not last, enjoy your swim. You’ll be amazed with improvements!