The only tip I know of is to pee in your suit.

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"your horse is too high" - tigerchik

"My hands and feet got really cold."

Had that experience while wreck diving in the Great Lakes. In 40 F water at depth even the thermal gloves/boots often doesn't protect the hands and feet fully. It's a miserable feeling. Not much you can do except be glad once you're out of the water.

Acclimation works and helps. I spent a couple summers swimming in a pool that kept the water temperature in the 67-68F range and was closer to 60 during the weeks when they were having problems with an aging pool heater. (and yes, we did have a number of very low body fat types who showed up every day, and didn't seem to have any more of a problem with it than the more padded folks) Physically, your body learns to deal with those sorts of conditions over time. Mentally, there's also something that goes on where you learn not to notice the cold.

Years later, any physical adaptations from that time period, you'd think would be long gone. But I did a race in 67F degree water last spring with no wetsuit (I'm not going to spend $100+ for something you can only really wear for 1-2 races a year) and once I got past the first 50 or so yards, it didn't really seem bad or overly cold at all. Just a bit chilly, but nothing I couldn't cope with.