A little ballet couldn't hurt, either. Or at least, borrowing the basic exercise known as "Tendu" from ballet is a nice little warm-up thing that you can use to get the blood going in your feet while also teaching yourself how to point and turn-out.
Begin in first position with feet turned out, and as Vanessa mentioned, try to achieve this as much through the legs as possible. The heels should be touching together, but the toes will be pointed apart, perhaps somewhere around 90 degrees (or slightly less) for us common non-ballet-trained folk.
Point your right foot forward, with the toe maintaining contact with the floor. The heel will release from the floor. As the foot moves forward, try to increase your turnout (or at least prevent a decrease) by working the heel forward more than the toe. Also, prevent the "sickled" position of the foot by keeping floor contact as much as you can with the inside edge of the big toe, rather than the outside edge of the pinky toe.
Once the foot is fully pointed, you can begin to pull it back again to first position. As it pulls back, again work towards increasing the turnout by feeling like you pull *back* on your toe, more so than you do with the heel.
Repeat the forward point three more times, and then begin the same process, this time pointing the foot sideways. Keep the same things in mind as you point sideways. Heel forward as you point, toe backwards as you pull it in again. Inside edge of big toe, etc etc.
Again, three more times, and then point backwards, all the same. That's a total of four points in each direction, and then you can begin with the other foot.
Here's another good idea: Do this to music, say at about 130 BPM (Cha Cha speed or so). Each point should take 16 beats: 8 to point, and 8 to return to 1st position. After doing a full set of 12 points on each side, repeat the exercise, this time doubling your speed. Each point this time will take 8 beats (4 out, 4 in). Repeat again with 4 beats, then with 2. And if you can do it, try with 1 beat (1/2 beat out, 1/2 beat in).
That should take a whole song to finish. And after that, you'll feet should be nice and limber.
I hope this helps.
Sincerely,
Jonathan Atkinson