I know i just posted this...but I thought I'd post it here too since it very much applies to the topic and I added a paragraph at the end for you:
1. All acolytes to mine, All ghouls to wood.
2. Queue up two acolytes at necropolis.
3. Wait until you have 400 gold.
4. Build a graveyard.
5. Build a crypt.
6. Build an Altar of Darkness.
7. Ziggurat
8. Build Tomb of Relics
9. When crypt is done, build a 1 ghoul.
10. When Ziggurat finishes build DK; When graveyard finishes build 1 fiend.
11. Build another Fiend when you get enough money.
12. Build a Ziggurat.
13. When DK comes out get rod of necromancy at Tomb of Relics and use it on one of the corpses at the graveyard!
14. Go out and creep a green spot with 2 spiders + DK + 2 Skeles (from graveyard). *WARNING: MICRO NEEDED..tank with skellies NEVER with DK. It's okay to tank with spiders too...just don't tank with your DK*
15. After second ziggurat completes train another spider.
16. Upgrade a ziggurat to tower of your choice (Nerubian vs. ORC, Spirit vs. Others)
17. Keep building fiends and upgrade to Halls of Dead as soon as you get 210 wood.
18. Build third ghoul during tech.
This is the usual spider opening for UD. You get the 'Late Hero' here which usually makes harassment out of the question (because your hero is too late). Also this makes YOU more vulnerable to harassment and there is a very good chance you'll have a hero in your base whacking on your acolytes before your hero comes out! Or he might be whacking at your 1 spider you already have made, don't let him kill that thing! Don't panic when this happens, simply do the following...run your acolyte or your spider away from the hero as quickly as possible, also send your wood ghouls to attack the hero (unless it's DH with immo, that might be bad), your dk will be out in no time! And you should be glad you got the dk here because as soon as he comes out you need to train lvl 1 Coil and save the unit! If he's not leaving (probably because you don't have a tower) then run to your shop and get rod, make skellies at your gyard, also get Dust of Appearance if you're being harassed by Blademaster or any Nightelf hero. After hero leaves you can creep/tech whatever. If this early hero harassment is continuing to give you problems (because your base layout always sucks or you can't micro for shit) then upgrade ziggurat around step #11 or #12.
Note also with this strategy you'll notice no 'scout' is mentioned. As far as scouting goes, use skellies. I'll usually buy rod, go to green camp, kill weakest creep first, make more skellies from that dead creep, and send the first set of skellies (that were ressurected from graveyard) out to scout in both directions. It's good to do all that as quick as possible to give your scout skellies as much time as you can.
Also note with this strategy, it is viable to go to the enemy base once you get your fourth spider out. With DK+4 spiders+skellies you should go let the fun begin. See what you can do vs the enemy, micro your fiends, coil your fiends, and most important don't be afraid to run away and go back to creepin or something, chances are you'll end up doing that anyway since 4 fiends won't really do much, it's more of just something to do besides creep green camps..at least that's how i look at it He'll be off creepin too so you can go to his creep spots and kill his creeps or kill units he's tanking with. Either that or I like to go straight to their base and focus fire + coil to take out a few workers. I like this because it's fun if you can get even one worker to die, then you use your rod on his corpse and keep goin!
Now once you get to tier 2 you can either drop slaughterhouse, get lich, get statues, and then tech....or you can straight tech to tier 3, and drop slaughterhouse while teching etc etc...this choice is very situational...but for you asking how to mass fiends, I suggest dropping a second crypt during your tech to tier 2, and drop a slaughterhouse once you get to tier 2 for statues....statues are key when using mass spiders, so is burrow!! The biggest thing i notice when watching pros use fiends is how ungodly and imba it seems when they don't lose a single fiend in battle because they can burrow like...whoa...anyways, burrow is usually #1 priority at tier 2 when you go fiends, but for me it's actually not because my burrow micro is shit
(and i don't go fiends much anyways). Also note you ask how to go spiders vs melee like knights and tauren and abombs...well the answer is you don't because mass tier 3 melee will own your mass spiders in no time. Mass spiders + stats is a tier 2 strategy meaning you should push real hard at tier 2 (not teching to tier 3 unless you have to) and try to win.
As for micro, you gotta learn to hit 'A' (for attack) and hold shift and click on the units you want your spiders to kill in the order you want them killed. Always unarmored first because they go down easiest. And while your spiders are focusing, the key is use coil on spiders that are dying, or when you have no coil or want to save mana, you need to move the individual spider that is losing hitpoints to the back of the line or even back to your base. You want to try to not interupt their focus fire by moving them all at once, just move them one at a time...or burrow them instead of move them once they get low on hitpoints. Get to know your spiders so you know how to move them away, spider micro i think is real fun
