From twitter.com, another client or via an app?

Anyway, basic principles are the same. To send a message (note: NOT a private message) to someone, type the @ symbol, followed by their user name, i.e. If I wanted to send you a message, I'd write @Retroman65 followed by my text.

There should also be something separate to your timeline which just has messages to you in it (just these @ messages, not your private inbox). Without knowing how you're accessing Twitter I can't tell you what to click, but it should be called "tweets mentioning me" or similar.

I'll try @-messaging you now and see how it goes!

you don't follow so some conversations can look one side or in complete.
In general if you know somebody's twitter name you just update your tweet starting @stephenfry etc and they will get the message in fact if you include their twitter name any where in the message it normally show up in their stream. Most tweet if you are following someone you can click reply and reply to what they've said .
Also click around the tabs at the top that will show yout he different options although I tend to use tweetdeck so not up to date with web twitter layout.

Unless everyone follows everyone else, it's always going to be a load of one sided conversations. It's like eavesdropping in a busy pub.

And no matter how many times you tweet at some people they never, ever, even acknowledge your presence. And I don't mean celebs as I don't follow any (really).

... (to me for example), you'd put @MrRenoDakota (my Twitter name) in the white box and add your comment. The @ symbol MUST always be joined to the beginning of the persons Twitter name you wish to send a message to.

You can only see all comments in conversations if you follow all people involved in the conversation - otherwise you only see that part contributed by the person you follow.

I'm sure the www.twitter.com site has tutorials on this to help you through some of the more complicated ways to use Twitter.

Good luck! (and hope what I've written makes some kind of sense!)

If you, for example, send a message to me, then - in addition to us - anyone who follows both of us will see it. This might be useful for Word Massive-related issues. The only supposedly confidential way to communicate on Twitter is by sending a DM (direct message); however both parties must follow each other for this to work. So, for example, you couldn't DM Stephen Fry unless he followed you too.

Sorry if some of this repeats already-covered ground.

...if you see a conversation that you'd like to barge into - say David Hepworth and Archie Valparaiso are shooting the breeze and you'd like to be involved - then you'll need to preface your reply with both of their Twitter names. If you select reply on Twitter for iPhone, it will do this semi-automatically for you. 140 characters still applies though, so the more people you want to address, the more succinct you need to be.

some handy hints and tips there, appreciate it.

what does the #ff symbol mean please???