I found the Trevor Thom RT book 7 quite useful for this type of thing, when I was doing my PPL training. I learnt at a field with a FIS and was very nervous the first time I had to talk to somewhere with full ATC. They gave me strange things like squawk codes. I found the most useful RT phrase at this point, "Say again."
Make sure when you make your call that you are sure of position, height, direction etc, and make sure you are ready to note the relevant points they will give onto your chart or some such.
It may help you when passing your message to say something along the lines of,
"G-****, PA28, passing East abeam somewhere, heading 010 at 2500' on qnh 1025 Student Pilot on NavexVFR, estimate your zone boundry at time three five, with information India, requesting joining instructions."