efi site also offers clues : 5 posts by 3 authors.

Efi site not only helps in ids and validation, but also provides clues to the id of the plant.
To give an example, take this thread: Pali near Khopoli, MH :: Small plant for ID :: ARK2019-64
We all struggled to get the id. On searching efi site on Rakesh ji’s clue of Zornia, I found these top results
As it was not Zornia, I searched on Geissaspis and found the correct id and advised accordingly.
To give another example, take this thread: For Id Climber- 021109Jm1 – which was earlier wrongly identified as Uraria rufescens.
Rakesh ji has suggested Desmodium dichotomum as id. I searched for Desmodium dichotomum in efi site and got two species results:

In the search results of Uraria rufescens itself, I see ‘ … would it turn out to be Desmodium dichotomum ?’ 
Thus it shows that Uraria rufescens earlier also has been confused with Desmodium dichotomum.
So if someone posts Desmodium dichotomum in future, I will also check Uraria rufescens in efi site, in case somebody has not wrongly identified it and posted.
I personally use this methodology widely to get desired results.
So, it is advisable if the members follow this to get desired id and eliminate closely confusing species.

It was pleasant to find this post on top of mails.  

This is what I do all the time in my practice ……in fact it is established process in medicine. 
Based on complain, history, symptoms and examination findings, we doctors arrive at a set of diagnoses, 
…….called dd or differential diagnosis …….with help of investigations we rule them out one by one to arrive at 
one final diagnosis. Plant identification process is no different. 

Thanks, …, for pointing out the wider scope.

yes. agree …

…, yes, i try to avoid the term differential diagnosis in nonmedical groups, but it does slip out here once in a while.
As you say, its the same process in medicine and in Botany… zoology, etc etc
in reality its nothing short  detective work… forming an idea where to start and then going point by point and looking at what matches..
before our site was this well filled out.
I used to use this same or even more extensive strategy to track down id to my satisfaction, on google and books I have.
but now our site is so well stocked that it is where I start

Thanks … for more elaboration.