U shouldn't worry, the reason why u lag behind is that u are in orthodox tech group. That means an extra 10% cost on research.
A little difference in land tech is normally not decisive. However, there are certain levels, which really matter. These are called CRT levels, which substantially improve fire value and efficiency of infantry. The first such a point is land9, make sure u get there in time and make sure u don't lag behind by more than one CRT level.
There are certain tactics how to fight a more developed enemy. Just the major ones:
- Benefit from attrition, build forts and let the AI to siege them through winter time. General Winter can be more deastating than anything else.
- Avoid pitch battles, but rather siege several AI provinces. The AI tends to focus on a single province at a time, whilst u can siege several at the same time.
- Benefit from the terrian, let the AI attack through a river (-25% penalty), use large cavalry units on plains and large infantry units on hills. Avoid to the a similar favour to the AI.
- Take care on the morale of your troops, adjust DP settings and maintenance, if in wa,r accordingly.
- Use your leaders wisely, try to avoid pitch battles with enemy leaders.
These basic rules normally help to fight a superior AI. There are some country specific rules, too. I.e. as Russia, u have almost unlimited manpower and a high maintenance limit. Attack "en masse" and u'll rarely fail. Surround your enemy with troops and attack again and again. U'll loose a few battles and surely more soldiers, than your enemy, but u can easily replace any losses, whilst your enemies can't. At the end, the winner will be the one, which has bigger resource$$$$... and that's u!!
