When searching the FamilySearch.org and the IGI. Try a exact name search with both parents surnames only.
1. Enter both surnames in the last name field.... i.e. Gonzales Calvillo
2. Enter Country....i.e Mexico
3. Check the box (Use exact spelling)
This will give you everyone in Mexico with the parents Gonzales and Calvillo. Try different corruptions of the surnames. Calbillo, Gonsales, Gonzalez, Goncales, Goncalez. It can be time consuming....but it's better than not finding anything when in fact your families are really there...or until the LDS church can load all the extractions in.
It's true sometimes L looks like S's on documents. Don't be afraid to try it.....i.e Moya, Moia, Molla
Also, If you know the region, try a batch search....this is very fun. In fact I just taught a lady two weeks ago who was stuck on her family, and with this trick she ended up finding nearly the the siblings and where the parents were married.
1. enter last name only
2. enter region
3 enter state
This will give you everyone in that state, scroll thru until you find someone within your town and time period. It doesn't matter if there not yours. Select that person. Go to the area where the batch number is located. Click on the batch number. Enter any name you like in any field. I.E. fathers first name only.....best to use mothers last name in the mothers last name field. If entering mothers last name only all women will appear and sometimes you will find miss spelled names on the father...that's how I helped my new friend.
There is no need to enter complete names, sometimes less is better.
Have Fun....
Rose Gonzales-Hardy
Fresno, CA