Practice practice practice. Practice giving your reports while driving in your car. Think back to calls you've done, and just give the reports over and over until you can do them perfectly.
It can also help to write them out to figure out what order you want to say things in, etc. It's a good idea to be systematic about it, and always go in the same order.
You: Northeast CMED Northeast CMED, BillyJoe Ambulance 62 requesting a BLS entry note to the Podunk Hospital, coming from Salem
CMED: BillyJoe, go to med 52 that's med 5-2 for the Podunk
You: Received thank you, 52 for the Podunk
*change radio to 52*
You: BillyJoe on 52
Podunk Hospital: Podunk online, go ahead BillyJoe
You: Good afternoon Podunk, this is BillyJoe ambulance 62 en route to you BLS priority 3 with a 92 that's 9-2 year old female, complaining of lethargy for 2 weeks. Patient is A+Ox4, denies chest pain denies shortness of breath, vital signs stable and we'll see you in 5 minutes. Any questions or concerns?
or:
Good afternoon Podunk, this is BillyJoe ambulance 62 en route to you BLS priority 1 with a 44 that's 4-4 year old male patient complaining of chest pain for 1 hour. Patient is A+Ox4, describes the pain as 10/10 crushing chest pain. Patient denies cardiac history but does have significant family history. Blood pressure is 96/62 with a heart rate of 118, satting 96 on room air, skin is cool and pale. Patient has received 324 of aspirin from us. We'll see you in 8 minutes, any questions or concerns?