SQL

To see what queries are running
SELECT sqltext.TEXT,
req.session_id,
req.status,
req.command,
req.cpu_time,
req.total_elapsed_time
FROM sys.dm_exec_requests req
CROSS APPLY sys.dm_exec_sql_text(sql_handle) AS sqltext
To see current connections
SELECT DB_NAME(dbid) as DBName,
COUNT(dbid) as NumberOfConnections,
loginame as LoginName
FROM sys.sysprocesses
WHERE dbid > 0
GROUP BY dbid, loginame;
Fine tuning long queries
SELECT top 10 text as "SQL Statement",
last_execution_time as "Last Execution Time",
(total_logical_reads+total_physical_reads+total_logical_writes)/execution_count as [Average IO], (total_worker_time/execution_count)/1000000.0 as [Average CPU Time (sec)], (total_elapsed_time/execution_count)/1000000.0 as [Average Elapsed Time (sec)], execution_count as "Execution Count",
qp.query_plan as "Query Plan"
FROM sys.dm_exec_query_stats qs
CROSS APPLY sys.dm_exec_sql_text(qs.plan_handle) st
CROSS APPLY sys.dm_exec_query_plan(qs.plan_handle) qp
order by total_elapsed_time/execution_count desc