+1. One idea is to keep a check on your time/speed this week. Then, in about 3 weeks, check your time/speed again. It will be less. Then try to ride at the speed you did during the first check.

Voila! You are faster and fitter.

All the other stuff about making sure your bike fits you properly, your pedalling speed should be quicker in a lower gear than slower in a higher gear, is also valid. Don't worry, everyone goes thro' this stage. And in about a year, you'll find yourself giving advice to a newbie. In the meantime, get used to this forum. It is full of opinionated ignoramuses who slag each other off at the slightest opportunity. It would be so much better if only they'd realise that I'm right.

Keep at it and good luck