As already explained by Jim, the readback of pressure is mandatory, you'll
have a violation filed against you if you dont do ti, similarly all
clearances, but thats maybe outside your area of ops, so to speak.

When you fisrt call up, LISTEN first. That way you'll get to hear whats
going on and you WON'T talk over someone else except by chance. Like Jim I
use r/t all day at work (flying) and the occurrences of being "blocked" are
rare. If you LISTEN.

Also, if you lisrten you can glean a lot of information and so prevent the
tower having to repeat.

As for being tongue tied, well, just LISTEN first to get your ear in, the if
you have to, write down what you re going to say, especially pressures, nd
other NUMBERS that often confuse pilots (of all levels). Write down what he
tells you so your readback is clear and concise. Trust me, even full time
jet jockeys write stuff down...how those ATC guys expect me to remember a
speed, a heading, a pressure, a flight level AND a hosties phone number
beats me!

D