I find taking closeups quite difficult without a tripod, with a rather low ratio of "good" photos. When I use the tripod, I can use the live-view focusing and this greatly improves the number that are decent. Both Trever and Joel are giving good advice. Given the appearance of the background, I'm not sure that you need the flash, as the background looks pretty well exposed just from the ambient. So, place camera on tripod, choose a high f/stop such as f/11 or f/16, a slow shutter speed (to get the right exposure), use live-view to focus on the near side, and use your depth-of-field preview button to check whether you got everything you needed in focus, then shoot! Now, given that you will have deeper DOF, you will also get the background in more detail, so you may need to move around a bit to select a non-cluttered background.