Make slow actions and dont do anything loud that might scare it away. Hold out your hand and wait for it to come and sniff it. If it doesnt, then you can get some food and hold it out until it trusts you.
I'm no expert on cats, but i'd advise reading the book 'cat canfidential - the book your cat would want you to read' by Vicky halls or 'Cat detective' by the same author. these are VERY good books....
You can either blow kisses to them or have a cat toy (having a toy, however, will make them think you're going to play with them). Cats are very independent, so it's best just to let them come to you.
Feed it in your lap, make it come to you for food, try not to stand over it and look down they see you as a giant. Feed them at their level and pet it while it eats