Tips for Lol players going to play Dota 2

The Limited Heroes gamemode

The Limited Heroes gamemode is great for new players because its heroes are great for beginners. Give it a shot for a good while.

The playstyle of a hero

Doing research to figure out the playstyle of a hero combined with your experience is key to using it right. A good Dota 2 team has two supports, two carries, and a solo-mid carry.

Carries

The carries have to get experience and gold fast to get strong enough to carry the team to victory, hence the name. A few carries are Drow Ranger, Wraith King and Faceless Void.

Supports

The supports have to help keep the opposing heroes from stopping the carries from getting farm. Since the money goes to their team's carry, supports are usually less rich. Because magic is overpowered early on, they tend to be nukers. They usually do well by getting items that provide strategic advantages rather than increased stats, such as a Mekansm, which heals allies when used (and is reusable indefinetly). A few supports are Shadow Shaman, Witch Doctor and Crystal Maiden.

Solo-mid

The solo-mid hero, rather than relying on the supports to babysit him, has the towers instead. He has to outdo the other solo-mid hero on his own, but be sure to help him stay alive, too. They tend to be good at ganking. Common solo-mid heroes are Viper, Pudge(to be honest I dislike this one) and Sniper.
Buy Town Portal Scroll . They work.

Also buy Iron Branches

They provide the best stat boost per gold value in the whole game, limited only by inventory space.

Also also buy a Magic Stick

It gives you charges when spells are used nearby (not your own, sadly). Using it gives you 15 health and mana per charge, up to a maximum of 15 charges. It also upgrades with above Iron Branch to make a Magic Wand, combining the utility of both. Rarely ever a bad decision for most heroes, unless the enemy has few spells.

Observer Wards

If you are a support, buy Observer Wards to keep watch over areas of the map sensitive to your heroes (such as the rune spots in the river, ways in and out of both jungles, and your own lanes if the towers are down), along with Dust of Appearance and True Sight Wards for fighting invisible opponents and taking down their own wards. Also make sure to be there for every teamfight, use your abilities to help out, do not steal kills and stick to your carry like glue so they do not die.

If you are a carry, don't be overly aggressive and let the towers hit you in a chase too early on

You will become a monster in time, but it is crucial that you prepare for it with caution, so don't die. (That sort of goes for everything). Also get items to patch your weak points and buff your strong points. And no matter how much of a monster you are, still try not to die (even as Wraith King).

I will also recommend a hero; Tiny. Tiny is a very good carry (also a good starting hero, try him out) who can stay alive and wreck everything. He has good auto-attack damage, a ranged damage-dealing spell Toss that can initiate and save lives, a handy stun in his primary spell, a passive that shuts down physical attacks with mini-stuns as punishment, and a passive ultimate that allows your abilities, hitting power and movement speed to get even more strength. Sounds cool, right?

Obviously, he has some problems. Tiny is attack-speed dependent, so getting an item for that is a good idea. I would recommend Power Treads as a good cost-effective option to remedy this, since they give movement speed, attack speed and a neat attribute switch when you need it. (Tread switching is a bit weird, you'll find out soon enough). Another of his problems is the fact that when he runs low on health and mana, he does not want to risk his death in a fight. While most useful in the laning phase, solo-mid Tiny tends to get a Bottle. It offers health and mana regen when used, and can Bottle Runes for later use (very powerful indeed). How about a way to make him even more powerful? The Aghanim's Scepter will do. The Aghanim's Scepter is a common item on many heroes because of its useful stats, health and mana pool increase and the fact that it provides very useful upgrades on some heroes. For Tiny, a cleaving attack and bonus damage to everything he can do is very nice. Also being a carry, he can find the gold for it. (Tiny needs more items than just those C and it also depends on the situation).

The proper way to play Tiny is to absorb the damage; be the focus of the enemy team. Make them try to kill you. Don't worry as much as you'd think; you can take a lot of damage. The auto-attacking carries will despise your Craggy Exterior passive ability. Throw an ally or enemy at another enemy or ally to deal long-range damage to an enemy or to get an ally out of a bad fix (help your support, he is trying to help you and he will be grateful). Use your stun and auto-attack the enemy as much as you can when they are stunned. Hopefully you win the teamfight, but if not, get back and get healed.

Mind you, this is only for Tiny (it is also not comprehensive; do try to figure him out before using him in an online game, for I have not done him justice). Don't just stick with the default builds once you are comfortable with the game, they are but recommendations. If you feel or know something else would work better, try it out and look it up. Chances are someone has tried it.