Before getting to work, my first advice will be: Play carry. Train and learn to play a hard carry that needs safe farm to be efficient. While you'll be playing, you will notice immediatly what your support needs to do in order to protect you. As far as I remember, being the most experienced player in my party, I always played carry. Needless to say that when I switched to support I was able to protect the lane and offer safe farm for my carry as I had myself been carry for a very long time and I knew as a carry what I wanted my support to do. Now I understand that this require a lot of time but this is the best way to learn to support, I can assure you. For the moment I can offer you some tips based on my exeperience of the game, starting with....
How to react depending on the enemy lane
If you are familiar with all the heros, your first reflex is to foresee (depeding on the hero picked) what type of lane the enemy team will run and adapt your behaviour. If for any reason you feel you need more help in the lane, do not hesitate to bring one more hero and run a defensive trilane.
If you are laning against :
- A passive solo offlaner (furion, elder titan for example) : Zone him out as soon as possible (even at first wave). You must zone him out of xp range. Do not hesitate to trade hit with him. Those offlaner dont have a great offensive power, if you have enough regen (tangos) you can force them out of the lane and deny a lot of xp by stacking and pulling (see last section).
- An agressive solo offlaner (darkseer, weaver, clockwerk, windrunner). Usually zone him out with one more hero at the very begining, then stack and pull. Those hero have great killing potential even in 1V2 situation. They might get over confident and put themselves out of position which allow an easy kill (especially with Crystal Maiden when you have a strong slow and a great stun).
- An agressive dual lane : this often ends up as a 2v2 situation. In this scenario the best you can do is sit in lane with your carry and save regen for him (pull him tango). If the 2 enemy hero are strong laner just stay passive, deny creeps as much as possible an try to get back the lane equilibrium close to your tower. It's the responsability of your carry to not put himself in danger aswell. As soon as possible request a gank from your mid. If the 2 heros took a level advantage and if they both get killed you will gain that advantage back in seconds.
- An agressive trilane. Play as defensive as possible. They brought 3 heros here which means they are losing in xp and gold. You can take advantage of it by not dying. Winning versus an agressive trilane is really as simple as not dying. They will shortly fall behind in levels and either abandon the lane or get killed by your mid when mid games kicks in.
In any case : don't forget to buy sentries/dust if you are laning against an invisible hero !
Items you can concider buying
Those item will bring some lane sustainability and are affordable for a support :
- Ring of basilius : mana regen + armor aura (don't forget to turn it off in the laning stage so the creeps dont benefit from the armor and the lane wont push toward your enemy tower : a place where its more dangerous to farm for your carry)
- A headdress of rejuvenation : Good stats and AOE health regen.
- 2 or 3 sets of tango : you can share them or trade hit with the enemy without worrying since you have plenty of regen
- Remember that you can share ring of health/regen, if you are planing on building tranquil boots, you can temporary lend the ring of regen to your carry.
- Wards (obviously) : the following ward's spots are often overlooked, however they are great to provide lane safety for your carry :
1) To protect jungle on the dire side
2) This wards allow you to see if a gank is coming from the tower and cover the river entrance (dire side)
3) This one protect the jungle on the radiant side and even allow you to see the rune
4) This one allow you to see an upcoming gank from the enemy tower as well as the river entrance (if the enemy mid come with a rune for example)
Use them in the following order : When you buy your first set of wards, give one to the offlaner and put the other in the jungle (1 or 3). If you are on dire side and your mid need rune control, concider warding the rune spot at the begining instead of the nearby jungle. Once you can afford your second set of wards, ward the rune and ward the spot that cover the tower (2 or 4). Usually the time where your recieve the second set of wards match the timing where enemies start rotating to your safelane in order to gank your carry. If you can see them TP to their tower you can avoid unnecessary death or foresee a push, plus it allows you to see an enemy venturing too far in your lane and getting out of position : allowing an easy kill.
Asserting lane dominance
It might sound silly but : play agressive.. from the start. If people don't fear your Crystal Maiden, Frosbite them from the begining and hit them. people underestimate how much magical damage you can dish at low level. Dont worry about wasting your mana, you should get arcane aura at level 2 or 3 anyway and level it up at least twice. Let your carry last hit while you frost bite every enemy that come close to him, it works like a charm.
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