Try to avoid peak tickets - these are more expensive, and are usually sold for trains that get you into London before lunchtime.
Book as early as you can. Virgin Trains release their cheapest tickets up to 24 weeks before departure, and the Caledonian Sleeper releases theirs a year in advance.
The fastest train to London from Glasgow takes four and a half hours. The average journey time is five hours. Stations en-route usually include Motherwell, Carlisle, Oxenholme Lake District, Lancaster, Preston (Lancs), Wigan North Western and Warrington Bank Quay.
Most trains from Glasgow Central to London Euston are direct, although some have a change at Crewe. This adds about half an hour onto the journey time.
You can catch the train to London from Glasgow Central. Some services are available from Glasgow Queen Street, but involve a change in Edinburgh. Most trains are operated by Virgin East Coast, with an overnight service on the Caledonian Sleeper (every day but Saturday).
Direct trains from Glasgow to London arrive at Euston Station. It's also possible to take an indirect train to Kings Cross, with a change at Edinburgh Waverley. Euston and Kings Cross are in the same part of London, near University College London and The British Library.
Euston's underground station is served by the Circle, Hammersmith & City and Metropolitan lines. You can also hop on the Northern, Piccadilly and Victoria lines at Kings Cross station, 15 minutes' walk (or a short tube journey) away.
The first Glasgow to London train departs Central Station at 04:28 and gets into London at 09:07.
The last direct train to London from Glasgow leaves at 18:40 and gets into London at 23:34.
There's also an overnight service to Kings Cross, which departs at 19:00 and arrives at 07:00. This involves a six hour layover in York before changing trains.
Train timetables are subject to change: compare tickets from Glasgow to London to see the latest departure times.
From Monday to Friday the Caledonian Sleeper departs Glasgow Central at 23:40 and arrives in London Euston at 07:07. On Sunday night there are two sleeper services, departing at 23:15 and 21:43. These both arrive on Monday morning at 07:07.