Help a noob?

Heyo!

I just got my hands on AoE2 HD and i try to figure out how to play well against the IA.

I just can't build an economy fast enough, meaning i can't get a good military. Then the IA raid me with only their special unit that i can't beat with overwhelming numbers. I just can't get my defenses up fast enough and i always get destroyed... against the Standard difficulty IA...