If I were you I would for sure look over Brent Ozar's website: SQL Serverpedia and view some videos that cover performance monitoring. EG:

http://sqlserverpedia.com/search/?search=performance+monitoring

There are three tools for monitoring performance: Perfmon, Event Logs, and SQL Profiler and which tool you use will depend on what facet of performance you want to assess.

To capture data about the how the hardware is performing eg. System: Processor Queue Length, Network Interface:Output Queue Length, and Physical Disk: Avg. Disk Queue Length go to Perfmon. To get there type perfmon from cmd line.

To capture data about how well stored procedures, ad hoc sql queries, and events pertaining to TSQL are doing go to SQL Profiler. To get there click on Tools menu from SSMS and select SQL Profiler

For root cause research, pertaining to trouble starting or stopping an application, diagnose running out-of-space issues in the transaction logs or database files than go to the Windows Application Events Logs. To get there click Start->Administrative Tools->Event Viewer. Also can go to SQL Server Logs by typing sys.xp_readerrorlog which is also found in MSSQL10.MSSQL\MSSQL\LOG\errorlog.

It's a start.:-)