I have done quite a few open water swims and I'm a fairly strong swimmer. It has taken me quite a while to get used to it but now I much prefer them to a sprint in a pool.

My advice is definitely practice your freestyle and close your eyes while your face is under water. If it helps you to give yourself more of a break, try rolling over more on whichever side you breathe and glide a little before you start stroking again. It can help you avoid some of the waves too!

I have a friend who combines free/breast, but only once she gets out of the pack. The most important thing is to keep moving doing one stroke for as long as possible since you will change your momentum.

Good luck and happy swimming!