I just got the last section (1890-1909) of Snow's guide to FE's & IHC's. So I sat down and started to attribute my 1900 IHC. Frustration!!! It didn't match any of his descriptions. Confident that the problem was me, not the guide, I sat back and re-read his intro. Lo and behold I found the paragraph that showed me the error of my ways. Most of the coins that he has attributed are the major varieties (and some lesser varieties). Coins with DDO's, RPD's, etc. So my "normal" 1900 IHC has not been attributed by Snow. Okay, now I can go on to 1901. Of course I'd REALLY like to find a new variety like Charmy did.
Your most common will be repunched dates or misplaced dates, so that is a primary area to concentrate, but they are not usually worth as much as DD, shallow N, etc. Sometimes you have to look several times with a light from different angles to see it if the grade is in the lower AG-VG range. Good Luck! Jim