What hints are considered useful for a system admin to speed up large database import ?

compress it with Winrar or winzip and import them

Save the files in .csv format and perform a Batch insert using a query ("bulk insert" for example) instead of the regular importing.

try to write small script on kettle tool: http://kettle.pentaho.com/ it's very useful ETL tool

If you're using PhyMyAdmin, one simple way is to compress the .SQL file using WinZip or WinRAR and import the zipped file straight away.

You use any software to spilt the sql file into smaller files like (http://www.sqldumpsplitter.com) and then you can restore this files easily you can find a good explination about SQL Spliter here http://www.spotht.com/2010/05/how-to-split-large-mysql-database-file.html