I agree with all that Tiermann and Ismene have said. For me, the four things that are likely to make good photos of Playmobil are bright lighting, sharp focussing, good depth of field and avoiding camera shake (using a tripod helps this, so you are OK on that one). Oh, and good setting up, but this topic is more about the technical stuff, yes?
Without knowing a little more about your camera, it's not easy to give detailed advice. My guess is that you will get the best results by using the 'flower' setting (as you already said) and not getting too close (as Ismene said). If you take some photos and then check them carefully (on the camera's screen if it has one, or even better, by loading them onto a computer so you can get a better view), you will see if the focus looks good. If not, try moving the camera back a
little.
The other thing which helps with focus is good bright lighting which gives good depth of field (so close and more distant parts of the object are both in focus at the same time) and you get a better margin for error with focus. Technical note: in brighter light, the camera adjusts to a smaller aperture (hopefully), small apertures have better depth of field. You could try changing the ISO setting to 200 or 400; this may also give better depth of field, but it will increase the 'graininess' of the pictures when you crop and enlarge them.
I usually 'brighten' my pictures using software (ACDSee, brightening shadows) because even with good lighting, the colours often come out better when the picture is further brightened. And PM colours are so brilliant, I like them to look their best!
Hope this helps. If you tell us the model of your camera, it might be possible to give some more tips.