To do so manually in the Registry:
- Locate the context menu item in
HKEY_CLASSES_ROOT\CLSID
, e.g., fro Run as Administrator:

- You will likely need to take ownership to make any change to that key.
- Add a DWORD value,
flags
.
- Set the value to
0
to put it in the Rename section of the context menu.
- Set the value to
1
to put it in the Send to section of the context menu.
- Set the value to
2
to put it in the default position of the context menu.
See also Stack Overflow for more ways to change the display order.
N.B. Hacking the Registry, particularly where ownership must be taken, can be hazardous to your system.
Some of the links suggest alphabetical order applies within a section. For the Start menu, I've used punctuation and NBSP, char(160), to move items to the top of the list or bottom, but have not tried that for the Explorer context menu. Check an ASCII table, keeping in mind Windows may display some characters oddly or choke on others.