working on US, Massachusetts—Boston Tax Records, 1822–1918 [Part G][M3CY-NCD]
You can click on the pen icon in the toolbar (4th from the right) and get some handwriting examples. I think it is important to learn to compare handwriting on the actual document too. For instance, on your shared batch, for the second entry the initial is W. We know this isn't Jr, because later on the record we see the name Joseph and how the person writes a capital J. The same applies for entry 6 where the given name is True and the same capital letter is seen in Thomas and the r is the same as in Ward. I love when we find interesting names like True West.
I noticed you stopped at the entry with E. m and wonder if that made you question what that was - it is a code like o.c., so it wouldn't be indexed. There is another lowercase "m" later on, and probably you will find more on the reference images to verify that these lowercase letters are codes of some sort.
This is also this great video:
Learning to Read Old Handwriting - James Tanner - YouTubeYouTube · BYU Family History Library
There are some tutorials online that are great for learning penmanship styles. Here is a knowledge article from the Help Center that will lead you to them:
P.S. We would never type Jr into a given or surname field. We only type these titles and terms into prefix or suffix fields. Jr, Sr. II, III are suffixes and are ignored in this project. The extra instructions in the field helps, accessed by clicking on the purple question marks, provide these important details.