See if there's blocking which is causieng the query to run slower than usual
Have a look at the query itself, see if it can be optimised.
Run it with exec plan, statistics IO and statistics time on, and look for high cost operators and high read tables.
Consider changing indexeng to reduce reads and eliminate table scans and index scans.
If there's a specific query that you're working with, post it here and we can help you work through it.
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)SQL In The Wild
: Discussions on DB performance with occasional diversions into recoverability
We walk in the dark places no others will enter
We stand on the bridge and no one may pass