If you own Bitcoin, you can buy into Steem directly through Blocktrades. It's a slightly worse exchange rate than buying via an exchange and transferring, but not enough that first time or small users should take the additional risks of that process.
If you go to your wallet, click the drop-down to the right of Steem, and choose Buy, you'll see the Blocktrades page. You simply send your currency of choice (BTC, LTC, etc) and they send you the Steem at time of conversion. I've used it 5-6 times, and Blocktrades has an account her. It's on the up and up.
I had looked at that and wondered how the built-in tool compared to other options. There's a wallet I use on my phone so I'll have to see what the route is to turn to Steem on the platform for me. Appreciate you taking the time to outline these differences for inexperienced folks like me.
Personally, back when I had the cash,I bought at Bittrex and sent it to Steem. That way I was able to set limit buy orders under the market. Blocktrades is a conversion-at-time-of-receipt deal.