This is just a start, I hope that you editors will suggest items to be added to this.
EV Ordering
One of the more important mistakes, since it causes Doug's calc problems. The order of EVs should be HP / Atk / Def / SpA / SpD / Spe, and must use those abbreviations. Having correct EV ordering in other parts of the analysis (or past gen analysis) is less vital, but helps with consistency.
Pokemon specific Spellings and capitalizations
Most people don't have all the Pokemon on their spellchecker, and some Pokemon spellings are rather odd. If you want to check for these it helps to add
this lot.
OHKOes or OHKOs
As the spelling and grammar standards article states:
"OHKOes as the verb form (
Salamence OHKOes Alakazam.) and OHKOs as a plural noun (
Salamence scores many OHKOs.). OHKOed is the past tense (
Salamence OHKOed Alakazam)."
This is not understood by many newer writers, and it's often worth checking each instance with Ctrl-F to see if they used the correct one.
EV Total
The EV total should be lowered when possible without lowering any stats. This means that at level 100 you should never see any EV investment in a stat which is not divisible by 4 without remainder. So, no 6 HP EVs or 255 Spe.
"Resists"
Resists can only be used as a verb. People commonly use resists as a contraction for resistances, which shouldn't be included in on-site analyses.
Others
Quite a few points in the
spelling and grammar standards article are not always followed, so read through it and check back to it on anything you are not sure of.
