We're going to focus more on improving poorly performing queries, so we won't go into DB tuning too much. This is a complex topic, and there is a lot you can learn about indexes and how data is stored.
However, if you haven't run the Database Engine Tuning Advisor (DETA), then this is an easy step to identify if you have any missing indexes. Yet you should be careful when applying the recommended changes, as there are always downsides and tradeoffs to consider. For example, indexes make retrieving data quicker, but also make it slower to add and update records. They also take up additional space, so it is best not to overdo it. Whether you wish to optimize upfront, or take the hit later on retrieval, will depend on your particular ...
