There's no sugarcoating it: Dota 2 is a complicated game with a brutal learning curve. You can have hundreds of hours invested and barely scratch the surface of the game's complex mechanics. Additionally, patches and balances are constantly changing the meta, so what you learned in the past might be outright wrong in the future.
The very first decision you'll make is which hero you'll use in the game. As a new player, you'll naturally want to play the easiest heroes with straightforward abilities. The heroes are not only great for beginners, but they'll also teach you the fundamental responsibilities of each role.
10 Wraith King - Participate Between Farming
Assuming you're playing with friends, the safe lane carry is the safest role for beginners. Wraith King is a bulky strength hero with a guaranteed critical strike and consistent self-healing. His ultimate, Reincarnation, allows you to cheat death by giving you a free life once killed.
Wraith King only has a spell and a half to worry about: one is a targeted stun, and the other summons skeletons to fight for you. Beginners should focus on efficient farming and taking objectives whenever Reincarnation is off cooldown. It's important to make an impact as a core and not just farm all game.
9 Juggernaut - Proper Itemization
Raw mechanical skills will only get you far in Dota 2; drafting, smart rotations, and playing the map are also important. As the hard carry, you're expected to use the space made by your teammates to accumulate gold. But your high network doesn't matter if you fail to itemize against the enemy team.
Juggernaut is an easy yet dominant carry who is welcome to any team composition. A good early pick who can't be hard countered, Juggernaut farms fast while having a high kill threat when Omnislash is off cooldown. Additionally, he has a flexible item path if the game calls for it.
8 Tidehunter - Initiate And Tank
Tidehunter is one of the most durable heroes in Dota 2. The Leviathan's job is to walk in the middle of the enemy team, cast Ravage to stun all the enemies nearby, then spam your abilities until the team fight ends, one way or another. Kraken Shell is a fantastic defensive passive that lets you shrug off most damage while cleansing negative effects like stuns.
Tidehunter can also take creep waves (basic units in the lane you kill for gold) and neutral camps (units in the jungle) quickly with Anchor Smash. Heroes who can efficiently farm are crucial for newer players to catch up after losing the lane. Finally, Tidehunter isn't a selfish pick since he has a versatile item path. For example, he can build around his ultimate with Refresher Orb, carry with Aghanim's Scepter, or build aura items to mitigate damage.
7 Bristleback - Dive Their Backline
Bristleback is easy to use because of his low cooldown and spam-heavy abilities. His kit relies on facerolling (spamming) on your abilities to stack their effects as well as Warpath's buff. You're expected to target squishy cores and mow them down while soaking up damage with your passive ability, Bristleback.
Bristleback is a feast or famine hero who can either dominate the game or pad the enemies' KDA (kill, death, assist stats). As a new player, you should utilize the hero's flash farming potential and innate durability to be a nuisance and make space like an effective offlaner.
6 Crystal Maiden - Dominate The Lane
Crystal Maiden is the quintessential support hero in Dota 2. She has two strong nukes with negative status effects, global mana regeneration for her whole team, and a powerful teamfighting ultimate. You can never go wrong with picking Crystal Maiden since she can help her team by simply being in the game.
Dominating the laning phase is a huge help for your carry since this accelerates their farm. Crystal Maiden has a very strong kill potential if you can soften the enemy with auto-attack harass before blasting your nukes.
5 Jakiro - Destroy Towers
Jakiro is a dual-headed dragon using ice and fire to control and damage enemies. While all its spells are skill shots, they have a lenient hitbox because of their long-range and wide cones. Jakiro excels in teamfights because the hero's kit is built for taking on multiple combatants simultaneously.
Jakiro is good at pushing since it can shove creep waves without any effort and destroy towers with Liquid Fire. Coordinate with your teammates to knock down their objectives. This forces enemies to group up and defend, which is favorable for your abilities.
4 Vengeful Spirit - Gank Their Cores
Soft supports are expected to roam around the map, ganking and finding key pick-offs (kills). Vengeful Spirit loves nothing more than small and isolated fights, where she can jump on the enemy for a fast kill. New players should get Aghanim's Scepter since it creates an illusion that uses all your spells, letting you fully commit to diving their cores.
Nether Swap is an easy-to-use ultimate where you swap positions with your target, practically guaranteeing a kill if you can swap their cores into your team. Vengeance Aura encourages allies to stick to Vengeful Spirit for that sweet attack damage bonus.
3 Ogre Magi - Protect And Enable
Ogre Magi is a tanky support who loves to brawl and skirmish. At first, Ogre Magi's kit seems underwhelming: a high-damage stun, a long-range slow with DPS, and a speed steroid for your allies. But, his ultimate adds a luck-based mechanic to your skills, which can cast any of his abilities multiple times.
Ogre Magi is an excellent enabler who can buff up his cores while disrupting the enemy. It's impossible to miss his abilities since they're all point-and-click, freeing your mind to think who to pummel with crowd control instead.
2 Zeus - Control The Tempo
Mid is the last lane you should be playing since you have no allies in the lonely lane. When you're ready, Zeus is a safe pick who threatens the enemy team by existing. Thundergod's Wrath nukes the entire enemy team, no matter where they are on the map.
Zeus has a consistent laning phase because of Arc Lightning, allowing him to shove the wave while harassing the enemy. From here, you can control the game's tempo by helping other lanes. Zeus has an easy kit that lets you concentrate on roaming as expected from the mid laner.
1 Sniper - Positioning And Prioritization
Sniper is one of the most recommended beginner heroes, and for good reason. Kardel has the longest attack range in the game, outputs tons of damage with little effort, and secures eliminations from screens away. He also excels at taking objectives because of his superior range.
Sniper is a pub stomper (dominant in public games, usually with random teammates) because he's great in uncoordinated teams, but against a stack, you need to mind your positioning. Kardel is a glass cannon with a defensive ability locked behind a shard. Learn to prioritize targets while also valuing your safety as the core.