dont stress to hard till you do it properly. charge that battery to 12.6v make sure you.threads are clean for each cylinder and that the compression tester is seated and tight on each plug. make sure the cylinders are not completely dry using a few drops of oil or injectors still plugged in.
have to eliminate variables to get solid results.
same with jump starting, rating of leads, clean connections on both problem and donor car, donor car raising the revs to 2kish when trying to start, also problem cars voltage cant be too low either as it still wont kick. (not everythings black and white)