Have you seen those little leaves on Ancestry? They kind of wiggle when you mouse over them. They're just asking for you to click on them.
On Family Search there's a section at the top right of each person's page for "Record Hints". It's the same kind of thing.
Want more hints?
There's one simple thing that you can do:
Make sure that the information on your tree is computer-friendly!
The website is using the name, dates, places, and family members you have listed on your family tree to look for records. You can get more hints by making sure that those things are in standardized formats that computers can understand.
For example, most of my tree comes from a tree that my mom made in the 90's. I've uploaded it to FamilySearch, Ancestry, MyHeritage, and Find my Past. But when my mom made the tree in the 90's, the standard formats were different. Some of the places are "Guelph, , Ontario, ". Those extra commas leave a place to add a county and country, but they confuse the computer. I know (or I can find out) which county and country should be listed between those commas and I can get more hints by adding the extra information to my tree.
Whenever you see something weird on your family tree, fix it! Correct misspelled words, make places more specific, add all of the family members that you know about. When the information on your family tree is easy for a computer to input into a search, the websites will send the search results to you. Then all you have to do is evaluate them and add those sources to your family tree. Easy, right?
Have you had any luck with hints on any of the family history sites that you use?