Hi! This is my first build guide but I think it's pretty good. Everyone I lane with loves Soraka by the end of the game. Now, I get to try to teach you how to replicate that. However, during laning, you will be doing a lot of minor damage and A LOT of babysitting. Your ult will save lives all the time. To play this build, you need to keep an eye on the health of all your allies. You should try to lane with a carry or a tank so that one of two things happens:
1) Your tank absorbs damage and you guys use the tower and lovetaps to kill enemies
2) Your carry has enough dps to mess up enemy champs. Your heals will be strong enough to keep him/her and you alive.
Since this is my first guide, constructive criticism is greatly appreciated!

You're playing a support first and foremost, don't forget that. Sometimes you have to die to save your team and that's fine. The magic pen runes are here for the times that your team doesn't need a healer and needs more dps instead. The ap ones are just cause they're helpful the entire game. I mean ALL game.

This is a pretty intricate build, item wise. You can, of course, take the steps a little out of order but this is the order that always works best for me. You will be squishy as all get out but your q, w, and e will be very effective. You build GP5 in the beginning because that way the carry or tank you are laning with can get the farm they need early game and you can still get your build going moderately quickly.

Early game, it kinda looks like you're screwed for damage but you aren't...at least not entirely. Granted, you will be doing minimal damage at the beginning but your silence will save lives and so will your high-powered heals. I save Starcall until you have no other options because it really isn't very effective against champs at all until late game and you shouldn't need it for farming really ever. Usually, your laning partner won't need you to fill up their mana so you should use Infuse to do little bits of damage to whoever you're laning against. On the flip side of that, if you have someone like Veigar or Fiddle, use Infuse more as a silence to take out some of their dps instead of using it to deal damage. Also, it will be your main form of damage early game since it is FREE and much more powerful than your auto-attack. Trust me, it works.

These are pretty simple to explain. Flash is so you can get in or out as necessary. Heal is so that you can save people, yourself included sometimes. You can, though I don't advise it, swap Flash for Exhaust.

Just some last little tips. You need to play carefully but don't be afraid to be aggressive. Until you get Starcall, your goals should be keeping your teammates alive and to have ABSOLUTELY NO MINION KILLS. The only exception to the second one is if your partner dies or recalls, then you should farm and farm hard. Neither your partner nor your minions stand to benefit from you not killing enemy minions so kill as many of them as you can because then at least someone benefits.