Start small - I started out swimming 1/2 mile total out and back in Lake Washington, Seattle. Pick a point to swim to. If you have a GPS you can actually gauge distance accurately, but if you're swimming along the coast, look on Google Maps to estimate distance with landmarks. 

Gradually increase time and distance - I went from 1/2 mile to 1 mile to 2.5 miles to eventually my longest swim of 10K (current assisted). If you're trying to swim without a wetsuit, same goes here for time and distance. Start small and pick landmarks, focus first on time in the water when swimming skins. If you've never swam in cold water, start with 5 minutes! A general rule is a minute for every degree - this is just a guideline and it's most important to listen to your body and train gradually. For more information, here's a great overview of cold water swimming benefits and safety. 

Find a community for support - I swim with the Notorious Alki Swimmers and Western Washington Open Water Swimmers Facebook group. This community has been immensely supportive and has taught me everything I know about open water swimming. They're consistent and keep me motivated. Plus, they're so fun to be around! The open water swimming community is small and niche, it seems like everyone knows each other! Find your local swimming group - swimmers are friendly people all around the world! 

Swim in a pool to train - I really dislike pool swimming now after swimming in salt water regularly, but it's necessary to train for long distances. Before COVID, I swam with a Masters team 1-2x a week at my local YMCA. Do yourself a service and train in a pool! With pool swimming, you'll do more interval training to help increase your speed and endurance, all which helps with OWS. 

Get Warm Quick - If you're swimming in really cold water for a long period of time, you're at risk of hypothermia. The good thing is that you can adjust your body to the cold! It's amazing but it works - especially if you swim consistently. Start small, increase distance and time without a wetsuit. Bring socks, a swim parka, a hat, and warm clothes to change into ASAP when done swimming, especially if you're trying in skins. It's best to start warming up with layers of clothing, doing squats or jumping jacks (these movements generate the most heat the quickest), a sauna or hot air from a car. Do not take a shower too quickly before you have properly warmed up - you can run the risk of passing out in the shower. I advise reading more about vasoconstriction and the risks of hypothermia. I linked a very informative hypothermia lecture from the South End Rowing Club in SF Bay in the Resources page. 

Be Safe - Swim in groups or with another person, consult others who know the area, swim with a buoy and if you feel deeply unsafe, trust your gut. 

Test the Water - I always like to swim casually in new water the day before a long swim in the same water. I recommend this for the mental preparation more than anything!