I haven't done much special customization on the ThinkPad, other than updating the BIOS in Windows (it's dual boot) and changing the BIOS sleep setting. The sleep setting disables "Modern sleep", where the computer stays awake when sleeping, which isn't so well supported in Linux.
Currently I have 11 hours remaining, on 78% battery charge with a fairly dim screen (I use a setting to prevent the battery charging fully to extend its lifetime). Powertop shows a draw of 4.1W. Strangely the computer seems to run hotter in Windows and the battery lifetime is a bit shorter.
I'm using Ubuntu 18.04, running KDE. The laptop (Carbon X1 6th Gen) has a very nice keyboard, red trackpoint, 1TB NVMe SSD, 16GB RAM, i7-8550U CPU and a 2560x1440 display. It also has USB-C plus a couple of USB-A and HDMI sockets.
