EDIT: the main goal is to move out at 7min with 3 liberators and air-ground attack (on 2 bases) and start harassing behind enemy mineral lines. Keep producing 3 liberators at a time and hellbats on ground for the follow-up push.
I have played beta for a while now and I came up with a liberator build that seem to work really well at my level at least against both zerg and protoss. I am usually silver league but I sometimes beat plat and diamond players, there is like a huge standard deviation in the way I play even though the mean must be silver xD
The things is I have no sense of timing, when to take the 2nd, 3rd and 4th gas for example is mostly random for me.
So here is my build overall:
14 depot - gas
15 2nd depot (i always wall off)
2nd gas somewhere in between
about 20 supply reaper + expo
and that's about my supply tracking xD
Then I put a factory and start producing mines as I found it is my only way to defend vs a roach push or adepts with that build. I put 3-4 in front of my bunkered wall.
starport + armory
I put 3rd and 4th gas almost immediately after the expo is up.
techlab on starport + second starport with reactor and research the air-ground attack.
Move out when you have 3 liberators and try to lock enemy expo or harass any way you can. Vs zerg i always try to get a spot where i can shoot the larva since they OS them and if they are not well prepared you can put 2 libe on an expo and 1 at the 3r or main, also eggs get killed fast so it can really ruin their production.
Keep producing liberators and hellbats with the additional supply. When you have 5 libe I found it's really hard for zergs and toss to engage into it. even stalker and hydra get useless if you carefully place the target areas.
I always upgrade the mech upgrades to 2/0 for the follow-up libe-hellbat push (i am usually on 3 bases at that point) with around 10-15 hellbat and 5 libe if i didn't loose too many liberators during the harass.
I think the build is best against zerg although I used it efficiently vs protoss too (but i think going libe-bio would be best against them instead of hellbats?). Zergs basically can't go muta nor roach against it, they have to invest in tons of static defense and make hydras who won't deal very well against the libe-hellbat push after the harass.
I wondered if some wiser terrans could help me refine my build and make it more efficient with fixed supply/timing objectives to put down buildings and gases, when to start which upgrades etc.