brief answer
think……..AIDA……Verdi's opera

A- attention
I- interest
D – desire
A-action

always pay attention and listen carefully ( if you miss one important word someone says ) it changes the whole complexion of whether/ what/ and how you respond.

show interest in everyone you talk to, or they talk to you.
if fact dont just show it….be interested.everyone has a story to tell.
and then respond, mirroring the fact that you have heard and maybe ask a question or two about, what they have said

desire…..to want to succeed and show it; also there has to be a sort of desire to create a committement between 2 people talking..a complicity..an empathy,
I which is a word you will hear a lot; but few people really understand it.
sympathy is saying sorry
empathy is saying sorry, now what can i do about it…..

action…….there has to be a beginning, middle and end to every communication. Let the other person know you understand and agree ( if there is agreement needed ) that you will do……..x/y/z……
and whatever you do……..do it.
never ever make a promise you dont keep !
it's a toughie…but say an appointment….never miss any; unless youre dead; if theres a problem…….one little phone call…..convinces the person you care.

if you are talking speech and public speaking…..
quick guide
mark twain…..used to say ( when he wrote his books )
tell them what you are gonna tell them ( start )
tell em, what telling them ( middle )
tell em, what you told them ( end )

also one of the basic of public speaking has nothing to fo with the subject matter, or your knowledge of it………….it is simply presentation !………..sound like / look like you know what you are talking about………..'' speak up…and win a jammy victory ''' !
References :
me…..too much to mention……sales / training / management etc