Looking to buy a Canon t3i. What else do I need? [Newbie]

paradiseexteriors posted a photo:

I'm making my first venture into DSLR-land. After many years of some Canon SD-series point-and-shoot digitals, and my iPhone cameras, the wife and I have decided to get a "nice" camera to take photos of our events and travels.I think we've landed on the t3i kit (default body/lens) to start with. But what else do we need? Any recommendations so I don't get slapped with the newbie-tax by the upselling salesman at Best Buy or whatever? via /r/photography ift.tt/1uuMnGi

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