[strof51]

The only thing that I would do differently to Kendal's excellent advice is a tip our trainer gave us, its to not worry about getting your dog to sit just praise them for their recall. Use treats call her in get hold of her collar praise and give her her treat, send her off then call her in the same collar ,praise, treat, she will soon release "if I come back I get told how good I am and get a treat".
Even now if I recall Poppy she stands with "the where's my treat look".

 

[strof51]

You can use any type of whistle. I use 1 sharp peep to get the dog to stop and turn then 2 sharp peeps for come, also I hold my arms out at shoulder hight forming a cross this gives your dog something to distinguish you with at a distance.
Hope this helps.