I'd say.. no, to the lucrative career, mm.
It depends on what you want to write though - I write mainly for dog magazines (ok v outing, don't really give a shit)... so that's a topic I know a HUGE amount about as dog training/behaviour is also my day job.
I have also written copy for a variety of businesses - it is dull, it is mind-numbing and sometimes bizarre, but if you have the skill of turning a handful of facts into a useful bit of copy.. great :D
I haven't done any of the courses or joined any sites, but I guess if I wanted more income that way I might advertise that I copy write and give some examples, and then pimp that round the types of business I'd like to work for.
For magazine work (and there is v little money in it, also, you get paid the month AFTER publication and they will sit on even requested articles for months sometimes!), look at the style, and look at their website for submission guidelines - anything submitted incorrectly will almost certainly get binned, so know your market.
I combine writing with freelance cartoon work, 'proper' art and the dog training/behaviour, and over the last 20 years or so have built up a network of people who know me and know what I can do.
Off the top of my head the last few jobs have been:
Advertorial for a beauty salon
Cartoon of a woman hitting a man with a bag of sprouts
Article on walking dogs
article on separation anxiety
logo design for tv production company
illustrate a kids workbook
I don't want to be a negative nellie but there are SO many people producing super cheap or even free content, even though most of it is incredibly low quality - its a hard industry to make a living at, I'd recommend having something else you can do as well (or several somethings!).
Magazines pay very little and thats not changed, in around 2002 I was getting £75 for an 800 word story. Last year I got the same! The latest piece I actually published on my blog and the magazine editor bought the print rights for what is a 4 page feature, for just £50. A mate who writes for another mag is getting around £120 for a multi page feature, and she's a 'name' in the industry!
I've waffled now and I've no idea if any of that has been helpful!