Can anyone share their actual teaching experience?

It is very rare to find out a person's ACTUAL teaching experience. Most of them are about life styles and how employers treat them etc. The closest i've ever learned was the students are lazy, many cheat, the school system has always been like that, there are some bright ones who actually care, etc. But nothing that states that based on your teaching experience, you should know at least XYZ amount of info on grammar, etc. Or I never had to prepare my lessons the class before due to the fact that everything so so easy....something along those lines.

I will be going to teach at a University at the preparatory level and I have no prior teaching experience. Only limited teaching experience was in CELTA during their few hours of mandatory teaching. Anyone else has experience teaching at the level in other colleges/universities? What kind of books you have used to teach it (I know it varies but share anyway)? How basic is this level? How easy or hard is it to plan for students at this level? What are things you didn't expect? Anything about the actual teaching itself?

Any help with this regards will be very appreciated.

Thank You