Slow queries on production Server I am a developer who has been asked to look at a database slowness issue.
I have had a look at the waits on the server and retrieved the following using a query from Red Gate's wait stats white paper.
The results are:

Wait type         wait_S            Resource_S     Signal_S     WaitCount      Percentage

PAGEIOLATCH_SH      393375.51       391289.91      2085.59      76733247       32.60

CXPACKET            367110.76       334340.19      32770.57     34663540       30.42

OLEDB               84136.77        84136.77       0.00         78106          6.97

SOS_SCHEDULER_YIELD 77896.38        15.97          77880.41     254840824      6.46

PAGEIOLATCH_EX      65944.98        65550.98       394.00       16298376       5.46

ASYNC_NETWORK_IO    45579.23        32512.01       13067.22     125659899      3.78

WRITELOG            37415.61        35457.02       1958.59      18559390       3.10

LCK_M_IX            36602.81        36587.52       15.29        67118          3.03

LCK_M_X             35503.99        35494.55       9.44         32114          2.94

LCK_M_U             30464.81        30452.64       12.17        28824          2.52


Does anyone have any advice on what to do next?

Does CXPacket suggest a maxdop change?  The server is a virtual server showing 4 CPU's in windows task manager.
While by no means a dead cert, PAGEIOLATCH_SH and CXPACKET in equal weight can be indicative of parallel table scans. Without a baseline to compare with I'd suggest looking at the top CPU and IO consumers and looking for those which appear in both.