As Lisa explains search strategically means using Ancestry.com's advanced search tools. Use what you know about someone to establish and add to your search parameters. To narrow by category start with a wider search, then narrow it down by category to target your search results. Wildcards like * or ? replace letters in a name to help you find misspelled, mis-transcribed spellings of the names you are searching for.
The Don'ts are don't be tempted to trust that other family trees are accurate without doing your own research. And don't give up your search. The record you are looking for may not have been indexed just yet.
Thank you Lisa for helping make it easier to work on Ancestry.com. For more information about Lisa go to LegacyFamilyTree.