I found a website full of information of people in my tree. Rather than constantly switching windows to look at the info then go back an put in the tree; would it be possible to copy-paste the info into the program then convert that into a GEDCOM file?
I use the import/export from/to EXCEl feature a lot. Exporting your people to an EXCEL file would allow you to put the new info into the Notes section and then you can import it all at once. This may help
"Although it is theoretically possible to write a GEDCOM file by hand, the format was designed to be used with software and thus is not especially human-friendly"
Although it sounds nice what you're saying, it would be difficult since each detail needs to be assign to an ID. So I believe it's copy/paste for you if the information ain't available in any other way, and with the possibility to export it into GEDCOM. But then you wouldn't have asked, would you?
A nice tool to "dock" several windows on your screen easily when you're gathering information would be: http://allsnap.org/
It's free, easy and ingeniously. I us it a lot while multitasking on my computer.