What is the best opening strategy in Age of Mythology?
Solution 1:
You didn't mention what race you play or he plays when you select Jotunheim, but I'm going to guess Norse based on the theme of the board.
This is a choke point board and controlling the pass certainly affects the outcome, however, you also need to play the strengths of your race.
For the Norse, their strengths are quick, powerful rushes early in the game. If you're spending time building up reserves or defences you aren't playing into their strength. If you can develop a quick offence, you can prevent the walls from going up and start removing his economic base, crippling him.
Maximizing your returns involves using your god powers effectively as well, because you mention your opponent making a defensive stand, a rush seems the best response.
Hersir Rush using Loki
Loki specialises in his heroes, the Hersirs. A typical Loki strategy is called the Hersir Rush. You use a fair number of Hersirs and the myth units they summon to overwhelm your opponent's early defences. Once the Hersirs start spawning myth units it often turns the tide.
To make this strategy work you must aggressively collect food. If your main food sources are berry bushes, then immediately start harvesting them. Train and add at least 4 more Gatherers to the mix. Once this is going you can explore the immediate vicinity of your base, looking for additional food sources.
If your main initial food source was hunted animals you should invest in the Hunting Dogs ability and start gathering from the wild life in the area. Try to avoid harvesting your cows or sheep until they've fattened. As you're able, add the 4 Gatherers to the hunting party.
Once your food production is moving along nicely, build a house near your base and also add an Ox Cart and 2 Gatherers to harvest wood from a nearby grove (don't chase down single trees yet). As you're able add an Ox Cart and 2 more Gatherers to harvest gold from the closest gold mine.
At this point your berry bushes should be nearly or totally depleted and you should move on to animal food sources if you haven't already. Adding 2 more food gatherers at this point will help keep things moving.
This is a good time to get your Ulfsark to build a Temple. You can keep it close to your base if you're being at all pressured, or you can set it towards the pass if your opponent is playing defensively.
Now add in 2 more gatherers on wood and 2-3 dwarves on gold.
When you're able, upgrade to the next age.
From this point on you're looking to generate your Hersir army. They are vulnerable to infantry but the myth units they spawn aren't, so you want to have enough Hersirs to withstand an initial counter attack.
If he has already built the wall you might want some raiders or other units to back you up, but if he hasn't built the wall then you should be able to do a lot of damage to him quickly.
Solution 2:
I would say that the fundamental flaw in your brother's strategy is wasting resources on his defenses. The Norse are the offensive race of the game, so always play to that strength. If you have 4-6 longhouses and about 2 fortress you will be able to train enough forces to place him on the defensive, and offense always decides the game. If you can be constantly training soldiers he should never be able to move his army into any kind of offensive strategy. Just keep the pressure on his military and his economy any he will be crippled.
Also, to the guy who answered this fist, you have some valuable info on the different races, but the rule you always must follow is NEVER LET YOUR TOWN CENTER GO IDLE. You should constantly be training villagers or age advancements (heroes if Greek), and also never stockpile resources. If you see it in the bottom left of your screen, those resources are not being used. If you have 2,000 gold but only 30 food, move your miners to your farms or hunting grounds to equalize the imbalance. A villager should never be idle or producing a surplus.