The best thing you can do right now is just do drafts, and 6 sealed like you're currently doing.
IF you want to compete and potentially win a Standard Tourney you'll either need to buy packs, trade with the cards you have or check out Craig's List/E-bay so you can buy particular card or perhaps a premade set.
Your conclusion is pretty accurate a lot of so called pros just do exactly that. I would say this though techincally your best deck.. will be based off your local metagame. What i mean is they're might not be the same distribution or same types of decks being run at your local tourneys as with the proleagues. Maybe a certain pro level deck is noticeable cheaper than all the rest to construct, so everyone at your local shop runs that one. In that case your best off running a deck that can function but also can heavily counter that one, and that deck that you're playing might not even be played on the pro-level. Since for you, in this hypothetical scenario... in order to have a high chance of winning the tourney you just need to stop a certain type of deck.
That's pretty much the only difference.. pro decks are good and are just going to work regardless, they're designed that way, but you perhaps for your particular pool of opponent it may be best to build a different deck.
Cool you're getting into MTG... I personally don't care for netdecking, i like originality, but i do believe it's fine to learn from the experts who are posting online. I just don't like copying takes from the game IMO. If you happen to build a similar deck fine. Lastly you can look into OCTGN a free program that you can use to play people in many different card games online, very easy to use.. i use it, and really fun. Good way to experiment with a deck in any particular card game and can play with friends or random strangers in the many online communites that use OCTGN 2. Very easy to use, if you're interested in it PM I can help you set it up.
www.octgn.net