It’s not often the case when some novice players get owned by seasoned ones on public matches. Basically, if you are learning how to play Dota 2 by the hard way — that is, playing straight on a public match — you will have a hard time trying to get a grip of the game.
Trying to go this way of learning can be a little step of, instead, having a coach telling you what to do next (and why), or even going for the recommended Limited Heroes route if you are into smash your head onto things. Basically, by this you are trying to learn on the go, getting little or none about the information the game presents to you.
So, basically, you should get the main boundary down: information.
The Edge of the First Boundary
The Boundary that differentiates a good player from a total novice is not learning to play with a particular hero, or even controlling a hero. That is essentially learning how to play any kind of MOBA game. The (real) First Boundary in Dota 2 is learning what does all enemies and items do. It is that simple.
Learning what you are up against can be very decisive, because it tells you what you can expect from the enemy team. In other words, you know that Naga Siren can use Snare on you, trapping you down in your place, but as Anti-Mage, knowing that you can’t use Blink to escape once Snared is another thing. So, to avoid that, you try to Blink before that or mind the gap between Snare’s effective range and your hero.
Another example from the items stash. If you have an Storm Spirit, that relies heavily in his abilities, you can use something like an Orchid of Malevolence to silence and kill him, but it won’t do anything if you don’t stop him from building a Black King Bar, what gives magical immunity for 10 seconds.
Flexibility in Building
The next boundary is related to that, how items can relate to certain heroes strengths and weaknesses.
Almost every hero has a prefered choice of items. Almost always you should start with some regeneration items, boots, and then get your main items. Let’s say, with Storm Spirit, you main weakness is your mana pool, so building a Bloodstone will make your main weakness a strength, as you will be able to cast your abilities more often as the Bloodstone will give you high mana (and hp) regeneration.
In the land of Dota 2, “anything can work”. Heroes usually have one item in mind to get, but you can opt for other items depending on the line up. For example, as Storm Spirit, you could ditch your Bloodstone entirely and going for Scythe of Vyse, so that way you could transform anything into a cute pig ready for death… as long you have the money. Or why not, getting a Ghost Scepter so that well-farmed Drow Ranger doesn’t hit you while you are silenced by her Gust.
So basically, learn what every hero does, and what they’re good for. When you get to know the items, and what they do, you are half-step away to start enjoying the game.
Obviously you won’t remember everything, but that is what Limited Heroes mode is for. You can start with a limited hero pool available for everyone, so you can focus on learning the first 25~ heroes.
So after reading what these heroes do, go there and have fun. And lose your soul in the process.