From BOL

Logical reads - number of pages read from the data cache

Physical reads - number of pages read from disk

To reduce reads you need to look at a couple of things, first being query design, secondly being indexing. If your query is pulling a large number of records that could be filtered by getting a smaller set prior to pulling that data then you can always cut down on reads that way. With improved indexing, specifically with covering indexes, you can reduce the number of pages that are being read as well.

All of this is just a basic guideline but should be applied to the analysis of all the queries that are running in your production environment. A query like the following (not mine but got this from somewhere else so, no credit here) should help in getting those queries.

SELECT TOP 20

SUBSTRING(qt.text, (qs.statement_start_offset/2)+1, ((

CASE qs.statement_end_offset

WHEN -1 THEN DATALENGTH(qt.text)

ELSE qs.statement_end_offset

END - qs.statement_start_offset)/2)+1) AS SQLText

, qs.execution_count

, qs.total_logical_reads

, qs.last_logical_reads

, qs.min_logical_reads

, qs.max_logical_reads

, qs.total_elapsed_time

, qs.last_elapsed_time

, qs.min_elapsed_time

, qs.max_elapsed_time

, qs.last_execution_time

, qp.query_plan

FROM

sys.dm_exec_query_stats qs CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) qt

CROSS APPLY sys.dm_exec_query_plan(qs.plan_handle) qp

WHERE

qt.encrypted=0

ORDER BY

qs.last_logical_reads DESC