I highly recommend to look for real examples on Google Hacking Database[1] for more tips & hacks. The audience of this site are mostly people looking to use google to find exploitable websites, but it shows techniques used to narrow your Google Search.

1. https://www.exploit-db.com/google-hacking-database/

Filetype: is also a favorite of mine.

One thing to note when using filetype in bing by specifying xls it also catches other file extensions (xlsx) while google in my experience only would find xls.

Yes I use bing sometimes and especially when troubleshooting Linux error logs I find it parses a copy paste better. Just my experience. Important to note I do not use profiles.