How to properly join in a QSO on HF...

[N4CR]

If you want to talk on 75 meters, your starting point is to get up a good antenna and get a signal that can be heard. While there are plenty of friendly hams that will rag chew your ear off, they don't have fun when they are trying to dig a weak signal out to have a leisurely conversation.

So get up an antenna and get an amp. An AL-811 will do.

You don't need the biggest signal on the band, but it's really tough to chat when you are in the noise all the time.

I've never had a single problem joining any group on 75 meters. Listen first and see if it's actually a group you'd want to chat with and don't even try if it's not.

It's my opinion that to really stay connected on 75 meters on a regular basis, you gotta have an amp and a long wire. I prefer a 135' doublet.

[KH6DC]

I'm relatively new also, but one of the more common methods I've heard to join was to wait for a lul or when someone has finished speaking and quickly announce your call sign. Most of the time they will acknowledge the "breaker" and ask who you are . However there are some more clannish groups, particularly on 80,  who will ignore you or may even become annoyed. Just move on. It's them, not you!
In fact,there are several frequencies on 80 that one should actually avoid, IMO!

Ditto, in between calls or lulls, drop your callsign.  Someone will recognize you and if they're cool will announce your call new to the gruop, ask your name and where your QTH is.  If uncool they'll say this is a closed discussion or closed group, buzz off.  I've encountered both in my 19 years as a ham but mostly cool people.

73, Delwyn KH6DC

[W4VR]

Don't say "contact" or "break."  Simply give your call and someone will answer you.