How do I get started modding saves???

[nnaatteedd]

So like the title says, anyone have any advice, a link, or anything at all to help???

I'll explain myself a little better, I have modio and I've retrieved many saves, I've used the save editors that are built into the program.
Recently, I've stumbled upon forums with people opening up saves and creating save editors that are stand alone for each game. I have experience in programming and would like to make these.
Logically, the first step is to figure out how to open the save and see what does what. That is where I am at. I know saves are different for different games, but is there a general program for opening a save in it's hexadecimal form, or whatever form is used to modify the actual save data?
Any help at all is much appreciated. Also I hope this is in the right forum.

[Celldweller]

Here, this might help:

How to use a hex editor to mod a game.