you are migrating database to which version?

You planning for in-place or side by side up-gradation ?

Just keep in mind few steps

Run upgrade adviser to check for incompatibility for application/database server while upgrading.

if any warnings/errors found ,solve it before migrating database

if you are planning side by side migration follow below steps

ON current server

1)Backup your all databases (Including system databases)

2)script out your SQL server Jobs

3)take out Transfer logins script

http://blog.netnerds.net/2009/01/migratetransfer-sql-server-2008200520007-logins-to-sql-server-2008/

ON New server

4)Restore all USER databases from backups

5)run all the job scripts you got in 2nd steps above

5)Copy the output of the script provided in step 3 above and run it on new server