How to protect my carry?

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 immediately 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 experience of the game, starting with....

How to react depending on the enemy lane

If you are familiar with all the heroes, your first reflex is to foresee (depending 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 hits with him. Those offlaners don't have 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 aggressive solo offlaner (darkseer, weaver, clockwerk, windrunner). Usually zone him out with one more hero at the very beginning, 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 aggressive 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 responsibility of your carry to not put himself in danger as well. As soon as possible request a gank from your mid. If the 2 heroes took a level advantage and if they both get killed you will gain that advantage back in seconds.
• An aggressive trilane. Play as defensive as possible. They brought 3 heroes here which means they are losing in XP and gold. You can take advantage of it by not dying. Winning versus an aggressive 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 consider 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 don't benefit from the armor and the lane won't push toward your enemy tower: a place where it's 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 planning 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 protects 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, consider warding the rune spot at the beginning 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 receive 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 aggressive.. from the start. If people don't fear your Crystal Maiden, Frosbite them from the beginning and hit them. people underestimate how much magical damage you can dish at low level. Don't 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.

For more information

You can go check:

• My previous post about When to be aggressive or defensive as a support where you will find more detail about how to support in early stage and through the game.
• This video about stacking and pulling.