I'm gonna focus on incorporating actual scouting into my game so, newbie question: When do you send your scouting drone? Like specifically, is it at a certain supply? or time?
I see that you are also following FilterSC's build (as am I) so I will offer a little advice on what I'm doing. I used to always scout with the first drone made after my 9-Overlord but don't anymore and just focus on my macro early game. I still scout, just not with drones.
So for ZvZ:
I send my very first Overlord toward their natural expansion. My second Overlord (which is normally sent to my natural to scout canons or bunkers from Protoss or Terran) is instead sent a little outside my natural expansion along the opponent’s path to my base. The first Overlord will help spot zerglings coming your way if your opponent does a very early aggression and the second will help spot and also detect if he starts making banelings outside your natural.
I used to send my first Overlord directly in their base if positioning was close enough but I would then miss the zerglings coming my way if he decided to do a 6-10 pool so I've seen that this way helps me more. If no early aggression is coming my way as soon as my pool is finished I pop out 2 zerglings to scout and see what he is doing.
The ZvZ match-up I think is the trickiest because with the FilterSC build the 15-hatch can make it tough to hold off from very early aggression. But with experience it gets a little easier to know what to look for and how to react. Also having a spine early at each base (I believe part of the build) helps out quite a bit. Below are some of my replays with different early aggression situations and what I was looking for:
10 pool all in with drones:
http://drop.sc/313793
Best case scenario on scouting is if their base is situated where your first Overlord can follow the path AND still get into their base but in this case I would have missed the zerglings if I did a straight shot over. As soon as my overload caught the zerglings coming I used my larvae to make zerglings and popped down a spine. Kept my hatch going at my natural in case he attacked that first to buy me more time and then I would cancel at the last minute. But he didn't attack it and I was able to use it as well.
6 pool
http://drop.sc/313800
My overlord was able to catch the zerglings coming even though he tried to stay away from the overlord's vision. As soon as my pool hatched I threw down 2 spines because it seemed like quite a few zerglings. I was hoping he would stop at my natural to give me more time but he was smart to go after my main. I canceled the natural to give me more economy to hold them off. After this initial stop I didn't handle it the best but I was able to still get the job done.
Early zerg baneling pressure into mutas
http://drop.sc/313802
My zerglings at 4:30 saw that baneling nest so I had to deviate from the build and defend my choke and throw down a roach den early. During his attack I botched it a bit because I wanted to focus on the banelings and have two queens block my ramp to protect my main. Was able to get all of the banelings except one and I should have just let my drones mine because one baneling won't kill them.
As soon as the lair is done I always scout again as soon as possible. I think this is critical. The first scout gets you ready for early pressure but the overseer will spot what path they are going with their build. Because of this, even though my build was off, I was able to see that he had mutas and I dropped a hydralisk den asap.
Early zergling/baneling pressure large choke
http://drop.sc/311810
Even though I try to stick to the Bronze to Masters' build, I had to modify this a bit as well. With the large opening to my natural I knew it would be hard to hold off a lot of zerglings. But I saw he threw down his natural before me so I thought I was OK...
At the 5 minute mark I only see 4 zerglings and figure they were just scouts, but at 5:30 I see him bringing more so I plop down some more spines and my roach warren and gas. I didn't see banelings but I assumed they were coming so I placed my evo chambers to help wall off my natural. Sure enough, banelings came in as well as zerglings but since I had 4 queens at this point I was able to block the choke of my main (which I meant to do on the previous example) and prevent the banelings from coming in and eventually the roaches finally hatched to secure victory. If he attacked earlier though, it would have been a lot harder to hold off.
Early roach push
http://drop.sc/313762
In this case when I get my zerglings there at 5:50 I see a roach den so I'm assuming one base roach so I pop down a couple of more spines and situate my evo chambers to help hold off the initial attack while sticking to the build as much as possible.
For Terran and Protoss:
I send my first Overlord to the choke of the natural to scout for an early expand. If I don't see anything against Terran I then move just outside their natural to avoid getting sniped by a marine, for Protoss you have a little more time to peek in before his cyber core and stalker are done. Again, for both races I make a pair of lings with my first egg after pool is finished to get more info. Remember, timing is critical so make sure you’re hitting those benchmarks from Filter’s guide. If you see double gateway or barracks there's a good chance he's sending early pressure so throw down a couple of spines at your natural and keep those same lings just outside their choke to see when they leave. I like to keep one at the choke and the other at the tower close to the opponent. If things look good (no rush by the opponent), I will make another pair of lings, one for the other tower and one for their third.
For all races:
Make sure you have your Overloads placed around the map at strategic spots (along the path for Zerg as mentioned above) and to watch for drops (esp. against Terran). As soon as that Lair is finished I make an Overseer to scout again before pushing out with the roaches. Don’t forget to hit ‘C’ to drop another spy before scouting with the Overseer. The info gathered at this spot will help determine if you keep cranking roaches or if you go tech and expand.
Hopefully this helps. I've been working on FilterSC's build but trying to figure out how to scout and focus on early economy without having to send a drone. Feel free to post replays on games you have questions on.
Edit: the problem I have with scouting is that I feel like can never take my eyes off my base or my macro will slip. So I send scouts blindly to there death and then maybe I can see the shadow of an expansion on the minimap afterwards if I'm lucky. I need to practice macroing while watching my scout/army.
I hear you, that is why I use the overloads now instead of worrying about my drone. Just gotta keep checking that minimap. Very, very important. I think almost all of my early reactions to cheese posted above were just by checking the minimap.