Despite having a rather formal structure to writing orders, there are a number of shortcuts and abbreviations that have come about over the years.  Below, I'll list some of the more common variations on order writing.  At the end of the day, the important thing is that the orders are human readable, so bear that in mind when writing them.  Remember: you can never have more than one unit in a tile at a time!

Order abbreviations
Standard formAbbreviationsExamples
Hold
  • Unit Location HOLD
  • U Loc H
  • Loc H
  • Unit Location
  • A Ruhr H
  • Ruhr H
  • Army Ruhr
Move
(Attack)
  • Unit Location → New Location
  •  
  • Unit Location MOVE New Location
  • U Loc - New
  •  
  • U Loc M New
  • A Paris - Picardy
  • A Par - Pic
  • F Lon M English Channel
Support
  • Unit Location SUPPORT Unit 2 Location 2 → New Loaction
  • U Loc S U2 Loc2 - New
  • A Greece S F Bul SC H
Convoy
  • Fleet Location CONVOY Army Location 2 → Next Location
  • F Loc C Loc2 - Next
  • F Ion C Tunis - Greece
Note: Because only one unit may be in any given tile at a time, it is always acceptable to simply reference a unit by geographical location (you don't need which type).

Location abbreviations
ProvinceProvince TypeAbbreviation
Adriatic Sea Water adr adriatic
Aegean Sea Water aeg aegean
Albania Land alb
Ankara Home supply center (Turkey) ank
Apulia Land apu
Armenia Land arm
Baltic Sea Water bal baltic
Barents Sea Water bar barents
Belgium Supply center bel
Berlin Home supply center (Germany) ber
Black Sea Water bla black
Bohemia Land boh
Brest Home supply center (France) bre
Budapest Home supply center (Austria-Hungary) bud
Bulgaria Supply center bul
Burgundy Land bur
Clyde Land cly
Constantinople Home supply center (Turkey) con
Denmark Supply center den
Eastern Mediterranean Water eas emed east eastern eastmed ems eme
Edinburgh Home supply center (England) edi
English Channel Water eng english channel ech
Finland Land fin
Galicia Land gal
Gascony Land gas
Greece Supply center gre
Gulf of Lyon Water lyo gol gulfofl lyon
Gulf of Bothnia Water bot gob both gulfofb bothnia
Helgoland Bight Water hel helgoland
Holland Supply center hol
Ionian Sea Water ion ionian
Ireland (impassable) Land ire
Irish Sea Water iri irish
Kiel Home supply center (Germany) kie
Liverpool Home supply center (England) lvp livp lpl
Livonia Land lvn livo lvo lva
London Home supply center (England) lon
Marseilles Home supply center (France) mar mars
Mid-Atlantic Ocean Water mao midatlanticocean midatlantic mid mat
Moscow Home supply center (Russia) mos
Munich Home supply center (Germany) mun
Naples Home supply center (Italy) nap napoli
North Atlantic Ocean Water nao nat
North Africa Land naf nora
North Sea Water nth norsea nts
Norway Supply center nor nwy norw
Norwegian Sea Water nwg norwsea nrg norwegian
Paris Home supply center (France) par
Picardy Land pic
Piedmont Land pie piemonte
Portugal Supply center por
Prussia Land pru
Rome Home supply center (Italy) rom roma
Ruhr Land ruh
Rumania Supply center rum
Serbia Supply center ser
Sevastopol Home supply center (Russia) sev sevastapol
Silesia Land sil
Skagerrak Water ska
Smyrna Home supply center (Turkey) smy
Spain Supply center spa
St Petersburg Home supply center (Russia) stp
Sweden Supply center swe
Switzerland (impassable) Land swi switz
Syria Land syr
Trieste Home supply center (Austria-Hungary) tri
Tunis Supply center tun tunisia
Tuscany Land tus
Tyrolia Land tyr tyl trl
Tyrrhenian Sea Water tys tyrr tyrrhenian tyn tyh
Ukraine Land ukr
Venice Home supply center (Italy) ven venizia
Vienna Home supply center (Austria-Hungary) vie
Wales Land wal
Warsaw Home supply center (Russia) war
Western Mediterranean Water wes wmed west western westmed wms wme
Yorkshire Land yor york yonkers
Table originally published here