I would like to second two suggestions that have already been made:
1) tamp the dirt down before covering it. Doesn't need to be rock hard just get the 'fluff' and air out of it a bit.
2) relax - follow the basic rules and use one of the verified 'good' soils and you will be fine.
I put the dirt into my tanks dry and without removing anything from it but I did have to net out a netful of wood chips after filling it. Since I am not OCD about my tanks being sparkling clean it didn't bother me. Whatever makes you happy.