First swim in 10 years......

Accept the fact that the first month or two will be tough.  HTFU and get in the pool and build it up.  The only real tip is to get in the pool consistently and reclaim your fitness.

(i.e. there is no easy answer)

This was me 3.5 years ago, after 23 years of no swimming.  I'd swim 2 laps, stop rest, then go again.  I'd do breast stroke in between freestyle sets as sort of a slow recovery swim just to keep moving.  Eventually I could do 4 laps, then 6, 8 etc.  Took me about a month or so to get up to 500 yards, swimming 4-5 times a week.  After about 6 months I could do 3000 yards in less than 80 minutes.

Just keep trying, repeating, going back, you will get there.  After about a year and a half of that I changed gyms and joined a masters swim group.

Hi,

Was having the exact same problem and for me it was partly not having swam in forever, but more than that I was using up way too much energy with my kick.  Once I eased up on my kick, was able to swim much longer without feeling like I was sucking wind.  Tonight swam 500m without stopping--keep at it, it'll happen!

90% of the battle is just getting out there.  The fitness will come stroke-by-stroke.

Agree with everything that's been said, just another voice to add support. It simply takes time and consistency, and it's a slow development. It can be frustratingly slow to improve - to fight the frustration, take notes on what your workout was, so you can see the improvement in real numbers. Another weapon to fight the blues is to spend a good five minutes 'frolicking' in the water, really just playing around prior to and after your workout. It can help making swimming more of a fun experience rather than a droll routine.

You may hear a lot about form and how important that is to 'get right from the beginning', but honestly, just work on your swim fitness at first. As you get more in tune with your body in the water, you'll seek form improvements naturally as you start to feel your own drag.

This is my May 1, 2010 swim after nearly 20 years out of the pool. 

6 x 50 on 4:00
Total: 300 yards. 

By May 15th, I was able to begin the Ruth Kazez Zero to 1650 in Six Weeks plan.

While doing all this, the only drills I did were "thought drills." For example, I'd spend 50 yards thinking about the angle my hand entered the water, the next 50 about rotating my body, the next 50 about kicking…

I also read a lot and watched YouTube videos. The accepted ideas about a "proper" stroke had changed significantly since I was coached in high school.