In my experience early scouts die, quickly and unconditionally. Resign yourself to that fact and consider anything the starting scout does a free bonus.
It is possible to scout early, but it's difficult and relies partly on luck. I consider it an advanced strategy. As a substitute you can move your starting settler around for a few turns, it's fast and can see far.
Speaking of settling, the most important early resource is commerce,

. (Food and production are also the most important early resources, but slightly less most important than commerce.

) Seriously,

can solve

and

shortages,

and

are much less efficient at providing

during the early game.
Early game the capital provides about 8

(palace) + 1

(city square) + 3ish

(population working rivers, unimproved

resources) = 12ish

.
Compare that to a new city, which will be producing maybe 4

, if you're lucky. It will also bump up civic costs and maintenance, possibly army costs. They also cost oodles of

, and stop your city from growing which in turn costs population-turns working

-tiles.
Until you can start improving the surroundings, new cities don't add a lot of value.
So build a worker or two and start improving the surroundings, worry less about founding cities.
The first research objectives are whatever tech unlocks the improvements for nearby commerce resources. Roads are also a great boon to early defence.
The second research priority is

without needing resources; that means specialists or cottages. I don't have the energy for a specialist economy, so I don't have any advice on that.
The third research priority is happy cap boosters.
The fourth research priority is military advances. Warriors last a
long time, mostly because they are so cheap. Quantity can substitute for quality in the early game. And by training on barbarians, quality (promotions) can substitute for quality (high tech units).
Note that I said priority, not beeline. Depending on the specifics, lower priority targets can be acquired earlier. For instance, I understand specialist economies can easily go for an early religion, that provides a military unit, happy cap and possibly gold from a shrine. If you need copper and can research it quickly enough, you don't have to hit Education before Bronze Working.
The best place to place your early defenders is on a forested plains or grassland hilltop 2 to 3 tiles away from the capital, surrounded by desert. All squares are also covered with roads. This would allow you to attack passing units, in the desert with attending defence malus, and move back to the forest-hill in one turn. Always keep at least one fortified unit on the forest-hill, and if the position is about to be overrun, retreat.
That's a dream scenario though, but parts of the ideal defence can usually be found. I suppose Malakim have an easier time, due to their affinity for desert. Use workers to shape the terrain, cut down forests unless you are going to sit in them. This goes double for forests next to your cities.
A good defence is an aggressive defence. There is no need to escort settlers or workers if your army is already pacifying the area. There is an old thread in this forum that describes the basics.
Remember, the penalty for over-defending against barbarians is a large army useful for attacking your neighbour. Try playing as normal, but add a single expendable warrior to each stack. Be prepared to sacrifice that warrior at the drop of a hat.
When Orthus spawns, look at the Orthus-GPS. If he's nearby, gather a stack of about eight warriors and go Orthus hunting.