Yeah oil is very important.
When I first started out I thought hah, well I'll just use horses for everything! Then ill have plenty of oil!
But no...horses eat so much supply you almost end up with a net loss. If im really low on oil, all ill build is trucks. With enough trucks, artillery, and flak, you can do pretty much whatever youd do with planes and tanks, have the benefit of them being highly mobile, and take less losses. Also fighting with them doesnt use up oil. Making them generally a better investment.
A group of 5 light tanks, moving a few hexes, attacking, occupying, attacking again, can use up an insane amount of oil. For a stack of trucks, artillery and flak, the only oil being used is the oil to move from hex to hex.
Though its hard to lay down general rules for everything, as every map and every situation is different.
Eventually your playbook will fill up to the point where most situations that arise you can go, OH ok, this perticular strategy works best for this situation. Youll realize the opportunities you can capitalize on. That just comes with playin against people.
The two biggest tips I can give, is to have front hqs, maintain higher than 100% staff, and try to never fall below 80% hq power. And that Readiness is everything. If youre below 90% readiness, run for the hills.
Also production usually wins these games because alot of people dont pay attention the big picture. If ive got 10k production, and youve got 8k production, and im killing more of your units than you are mine, ima gonna win, skill or no skill. Territory is meaningless. It only has value if it has a production center, or cuts off units from a supply source. Always retreat instead of die if your on the defensive. Even if youre bleeding territory like a stuck pig, if youre killing more of the enemy than youre losing, and enough to offset a production advantage, youre winning. Nothing messes up a good offensive either than a fast moving front. That 1 horse or 1 truck the bombardment or bombing killed a few turns ago that the guy never thought to replace here or there is gonna string their units out all over the place, with some units advancing others getting bogged down, thats when you can make your wtfpwn counter attack and pray that gives you the initiative when the other guy goes into a defensive mode trying to figure out how you just did that.
It took me YEARS of 4x games to realize these things. Somewhere between Civilization III and Space Empires 4 it just sort of clicked.
Also theres little nuances to defense...like dont take the bait of killing off a division when its going to ruin your units entrenchment. Its hard not to do it when youre in the mode of "whatever hurts him helps me" but generally when youre on the defensive you want the guy on the offensive to hurt himself...cause you probably lost the chance to hurt him ages ago. If he never messes up, so be it, at least you tried. Cant win every time :)
Just got to always keep the snowballing effects of 4x games in mind, and not let it discourage you if you started out on the losing end of the map generator stick.
More production = more power = lopsided battles = massive XP gain = more lopsided battles = game over. The strategy of the one with lesser production is always to try and throw a wrench into that paradigm anywhere you can, while trying to diffure the snowballing effects so that it buys you time for the other player to make a mistake. Pretty much like going 2nd in chess, if they never make a mistake, so be it, you were bested that day, youll certainly get your chance at going 1st, ie having the most production, and itll then be your chance to attempt to not beat yourself by making a mistake.
Well said...yep, if you're playing someone with even average skill, if they have more production than you, chances are, you'll lose...it's just a numbers game in some ways. That being said, as you stated, if you can weather the storm, and hopefully catch him making a mistake, you might be able to pull off a miracle.