Troubleshooting SQL is difficult in itself, so it helps to have a couple of handy tools. Below are a list of some of the tools I find handy:
PAL: Performance analysis of logs. PAL can be used for SQL, and has two great functions. 1) To create the counters to collect perfmon logs. There was a time my manager came up to me and told me we had an urgent task to measure the health of the system. I was going to use perfmon, but what counters should I look for? Perfmon can help by providing the right counters to use. 2) To decipher and analyze perfmon logs using data visualization. I use PAL to load a perfmon log file, and PAL produces HTML output with text, based on common threshold, describing the health of the system.
SQL nexus: This is another open source tool.
SQL BPA: SQL Best Practice Adviser from Microsoft.