Back off the mic, don't yell into it or breathe into it, this sounds horrible
If you speak in a normal tone of voice and can pass your fist between the radio and your mouth that's a perfect distance

How do I find repeaters near me? Google, ask your local club, RepeaterBook.com,
ask if there are any more repeaters in your area once you make contact on one.
You’ll find that the topic of repeater operation, location,and operating
conditions of local repeaters will be a topic of discussion at times,
take notes. New repeaters pop up all the time and some even go off the air.
When searching for local repeaters using a list or recommendation

Scan the bands for those super sneaky secret discreet simplex hang outs
Start at 144.000 to 148.000 then from 420.000 to 450.000

The only way you’re going to know if you can reach them is by using them,
if nobody is talking you’re going to have to test it yourself.
The best method to do this is to say your call sign and add the words
testing or listening. Do not just key the mic and not identify,
it’s in violation of the rules and it’s super annoying to anyone listening.
When you call out on a repeater after your call say the repeater name or frequency to let other know what repeater you're on
Don't ask for a "Radio Check" but rather ask for a signal report, the phrase "Radio Check" is a term used on CB and GMRS
Just announce you call sign, if someone can hear you they will respond and then you can ask "how am I making it into the repeater?

Note that if you’re using a handheld radio (HT) the low power has its limits
and depending on your distance from the repeater you may not have a good enough signal to use the repeater.
Just because you see a strong return signal on the repeater doesn't’t
necessarily mean you are getting into it with a clean enough signal to
be heard. HT’s  are tough to use on repeaters because of the
low power and the stock antenna is usually not the best,
you’ll find that a good after market antenna will make a world of difference.

First rule for repeater operation is to listen, monitor the repeater traffic
and get accustomed to the type of conversations and how the flow of sharing a repeater with someone goes.  
If you hear content that is of interest to you all you have to do is wait
from a break and say only your call sign, nothing else. Using courtesy
when interrupting an ongoing QSO is key to being openly invited into the conversation.
If the conversation consists of how Aunt Martha folds bed sheets with her sister that might not be something you want to get involved
with but at least you can test your radio gear and after you announce you’re a new ham it may change the conversation briefly.

If you’re successful in joining, take notes, write down call signs and names.
When more than 2 users are on a repeater this is called a round table,
passing the conversation in order from one person to the next.
Set your TOT time out timer to 120 seconds this will prevent timing out the
repeater and burning up your radio if you sit on the mic or it gets
stuck. Don’t be that guy that times out the repeater

Leave a break in between your transmissions to allow others to join in,
do not Bogart the repeater by quick keying, take a break, wait a bit then key up when it’s your turn.
Also making announcements asking if anyone else wants to use the repeater to
call someone or join in is good practice as well. Common courtesy is
not so common these days, remember you share the repeater with many others.
Unfortunately some hams have a really bad habit of quick keying some may even do it purposely as note to be disturbed
This activity puts and unnecessary strain or heavy duty cycle on the repeater preventing it from coming up for air.
Most repeater have a TOT Time Out Timer that will shut down the repeater to give it a break.
Set your radio time out timer to something 120 seconds so your radio will warn you and prevent you
from timing out the repeater, you don't want to be that guy trust me.

DO NOT “kerchunck the repeater, kerchunking  is when you press the mic key and immediately let go without identifying.
Another annoyance and it’s a rule violation sending unidentified
transmissions, not the crime of the century but not cool. If you want
to test a repeater and check the return signal just say your call sign and “testing” or something.

Don’t forget to identify yourself,
just give your call sign every 10 minutes, saying it any more than that
isn't necessary and can be annoying. When the other users on the
repeater give their call sign or the repeater identifies that’s a good time for you to do the same.

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Now for some of the dark side to ham radio that you need to be aware of.
Hams are generally happy to encounter a newcomer and will congratulate you and welcome you to the hobby.
On some very rare occasions you may encounter a grouchy old guy who
doesn't’t like new kids on the block, the best way to deal with
someone like that is to ignore them and move on.
Generally other hams will jump in to defend you and call the grouch on his
horrible manners but just be aware it does not happen as much on VHF / UHF analog or digital, usually it happens on HF.

You may also encounter intentional interference from rouge unlicensed and even from sad angry hams
who will purposely jam a frequency and at times render it unusable. If this happens, completely ignore it,
don’t say anything about it or acknowledge it happening, this will only fuel
the fire and the perpetrator will continue to cause havoc if they know
it’s getting under your skin and is effective.
People that do this are looking for attention and want to get a rise out of people complaining about it.
As you are aware foul and abusive language is forbidden on ham radio, that doesn't’ mean it does ever happen.
Although rare you may encounter someone with a dirty sailors potty mouth,
sometimes we slip up and get over emotional and excited into the QSO we
forget we’re on ham radio. This is a family friendly hobby with little kids listening so if you
can’t say it at the dinner table or in front of your mother
don’t say it on ham radio. Watch your language you never know who is listening, in my experience for
every two people on the radio there are two more people listening to
you. Some guys like to just listen and potential newcomers might be listening too with a scanner.

On the subject of language there are some taboo subjects that are discouraged, politics and religion and drugs are the 3 main subjects
along with sex that cause arguments and hard feelings and really have no
place on ham radio. It’s not illegal to discuss controversial
subject matter but it is in really poor taste.
There’s nothing wrong with having a good debate and discussing some of these
topics but it usually ends with someone getting butt hurt. Use common
sense and good judgment when encountering these topics on the radio.
This is one of the reasons I don’t like HF. It's very common to run
into this there, some of the old timers get pretty excited and
opinionated, it’s best to avoid these types of QSO’s. Not all HF is like that, it’s just more common there.
Don't be that guy who nobody wants to answer or talk to.