I'm not a good player so this may not be good advice, but when I was starting out I put some thought and experimentation into an initial build order. My goal was to maximize early econ production under the very circumstances you describe (which is what a new player would likely be doing). Here's what I came up with.
Pregame: Start immediately adjacent to a mex spot in a cluster of three. Time spent walking is time you're not making metal or units.
Com: Facplop Cloaky Bots
Com: Area mex the three mex spots
While the Com is walking and building, get your factory making units:
Fac: Turn on repeat and turn off auto-factory-assist (should set these by default using "Initial States" in the Game Menu)
Fac: Set a waypoint a short ways ahead of the fac
Fac: Alt-queue a glaive
Fac: Alt-queue three rectors
Fac: Alt-queue four more glaives
Fac: Queue your early-game unit mix. Example: two glaives, zeus, two glaives, warrior, two glaives, zeus, two glaives, rector.
Alt-queue says "add this unit to the queue after the currently building unit, and don't add it to the repeat loop". This sequence will produce five glaives, followed by three rectors, followed by your mix on repeat.
Once you've got your factory busy, add to your Commander's to-do list:
Com: Space-queue two solars next to each mex
Com: Shift-queue assisting the factory
Space-queue inserts the solars into the build queue, so that the Com will build them in the right place and time as he's working on the mexes already in his queue. [ [i]
Second Edit: See below for clarification.[/i] ] Shift-queue adds the factory assist order to the end of the queue, so that once he's done building his three mexes and six solars he'll contribute his buildpower to the factory.
If you work fast, you can get all these build orders queued up while the glaives are coming out.
Spread the glaives out in a line somewhat ahead of your base to get some forward visibility and defense, but not too far - they aren't scouting, they're protecting.
As the rectors come out, give them build orders:
Rector #1: Cap mexes. Queue up a long series of nothing but mexes, starting with the closest ones and working in a single general direction outward (i.e. don't have him going back and forth).
Rector #2: Follow behind #1 and add two solars per mex.
Rector #3: Go directly to the best close spot for a radar (a nearby hill if there is one, or the edge of a clear space if there isn't one) and put up a radar and a defensive tower. Then start following in the general direction of Rectors #1 and #2 and add defensive towers and radars wherever it seems they'd be useful.
Give each Rector a long series of build orders all at once, so that they stay busy for a long time without further intervention.
As the Rectors set off on their tasks, use the Glaives to protect them. Don't just set them to guard - use them to spot and clear the territory ahead of where they're going, and keep them close enough to cover the builders but far enough ahead that you can intercept approaching threats.
With this build order I'm trying to do the following:
a) Minimize idle buildpower
b) Minimize m-stalling
c) Minimize e-stalling
d) Maximize output of useful units
e) Protect against early scouting and rushes
f) Maximize territorial control and economic expansion (i.e. GET MOAR MEXES!!)
g) Minimize the micromanagement - use automation and long queues of identical actions to reduce the amount of decision-making and mouse-clicking you have to do
What I'm not doing here is scouting. But it would be easy to take one or two of the first Glaives and send them off towards the enemy instead of guarding the base. Maybe add another initial Glaive to compensate so that you've got one or two scouting and four or five defending.
Also, if you can keep up with the micro, you could add another two Rectors to the initial set and send them off to build mexes and solars (one just doing mexes, the other following behind just doing solars) in the opposite direction from the first pair. The problem with that is now you have two fronts to protect, and not enough glaives to cover both fronts.
The nice thing about this build order is that it generates a ton of productive activity in your base while giving you just a few things to concentrate on - in the early stages, mostly you'll be driving your Glaives around exploring the territory near your base and protecting your builders, while your builders just go on doing their thing without your attention.