what were your biggest mistakes on your first game?

I remember I began as Germany (with no tutorial round) and went to war with Poland, The Netherlands, Luxembourg, Switzerland, and Austria. my army was mainly armored cars because I thought they worked the best against infantry but would have huge casualties when going against tanks. I planned to have a huge air force but ended up with 1 plane. I didn't know how to conserve materials so I (almost) ran out of food. I also ran out of oil when making tanks. I didn't place spies in any country because I thought they all needed gold. I didn't have a navy and only had about 10 units. what were some of your bad decisions?