All secrets of DOTA 2.

Support

• Are you losing the lane?
  Leave. The worst thing you can do as a support if you're in an unwinnable lane is stay there and soak up xp while doing nothing. Let him get solo xp so he's at least overleveled and underfarmed instead of underleveled and underfarmed. Oh, I should mention I'm assuming he knows how to play and doesn't over extend and die to get 2 creeps per minute and just sits back and soaks xp to get overleveled, you might have to mention that to him if he's bad.
  Now that you've left, what do you do?
  1) Protect runes for mid
  2) Gank mid with good rune
  3) Smoke gank mid
  4) Gank opponent safe lane
  5) Go to different lane and stay there to push forcing pressure off your safe lane (often called "making space")
  6) Hate on mid again
  7) Ward aggressively instead of defensively. People often think when they're behind they have to play defensive. However, warding opponent jungle and running at their AM while he's trying to farm can slow him down/get a tp reaction from the axe/wd and they waste time chasing you (again, making space)
  8) Smoke gank again
  9) You should have a level advantage on your cores from 2 solo lanes and you protecting mid, use it mid game to kill people and turn xp into gold
  10) See who's doing well on your team, follow them around (if they need +1 to kill, if they don't let them do what they're doing and just sit far behind them in case of ganks) and help them kill people so you get assist xp/gold and they're safer cause you can sacrifice yourself to make sure the person doing well doesn't die
  11) Hope your carry isn't full retard and can make use of solo xp
  12) Farm jungle yourself. It might actually be better your carry gets solo xp and you get jungle farm from pulls, but that's a judgement call.
  13) Stack ancients/large camp. Use judgement though, if your mid is getting pushed down at 5 minutes you're probably not going to get to farm those ancients. You can hang out while your carry kills it for some levels.
  Basically, there's tons of things to do when you lose laning phase unless you get crushed and die 3 times each. Then the game might just be over.
• Don't stare at the cliff while you're warding. When warding, shift queue. Place the ward and Shift click somewhere else so the motion is fluid. Want to make this worse for your opponent? Stare at a cliff you're NOT warding while you know they have vision of you.
• If you feel you're getting yourself into a warding war, stop dropping obs there. Maybe you can drop another sentry if you have a way to get vision of the cliff ward, but that's about it.
• If you have the room to carry a stick and 3 branches, keep it that way instead of upgrading into a wand.
• After you upgrade the courier, your next item should ALWAYS be a TP scroll. Suddenly being on the other side of the map is a strong surprise and easy kills. Even easier is TP'ing when someone is tower diving. Free double kill for you.
• Even if you're a support, don't let last hits go to waste. When pushing, try to be the first to kill the ranged creep When pulling, last hit those neutrals
• Fight the urge to TP to a lane when you're in the fountain. Keep the cooldown fresh and save gold for when you're actually needed.
• The scoreboard assist counter means NOTHING. What matters for kills is that you're around them. Assist gold is always evenly split among heroes in a 1300 radius of the kill, even if they didn't damage them. When you narrowly survived a dive, mind your position, but don't run back yet. If your team turns the fight you can maybe throw out another spell and in the worst case benefit from assist gold.
• Ask yourself this one question all the time: "Am I safe?" Always travel with someone else, even when warding. Looking for some farm? Take farm close to where your team is or a tower of yours. Are you going to iniate? Make sure your team is ready to follow up so you don't die.
• Always carry a TP from min 5-6 onward.
• If you are babysitting, focus on denying creeps.
• Don't single pull unless you want to push the lane.
• Always consider buying a smoke at the start of the game.
• Try your best not to pull at 1 Min game time as your carry usually does not have enough damage or experience to last hit under tower. Wait until the 3rd wave to pull and while waiting you can harass the enemy offlaner so that you carry can get some last hits and either get a quelling blade or his boots!