Greg Shchepanek The colours in this are promising as far as colour contrast, the light seems underexposed and i say that not so much because i think the photo may be dark but because you are at f3.5. You are at 1/60 sec shutter so you cant squeeze much more light out that either for handheld - for tripod answer is easy, slow down shutter speed.
For handheld a flash here may be your best options, apart from raising your ISO and risk noise. The flash will also allow you to increase DOF. Keep in mind your working distance and how it affects your DOF, as you get closer your DOF is rapidly decreasing and your chances of hitting focus are droping since you get about 3mm of DOF at 1:1 magnifaction at f3.5. Like all things photography there is a trade off for getting closer and the workaround is to either use higher f/stops or learn focus stacking. F3.5 may cover a flat object like a coin at around 1:1 but it wont do for a rounded object like this flower center.
In conclusion my recomended settings for this photo would be more like this : f/7 (at least, maybe more depending how much bokeh you want on the white petals) and flash. Use an external light, like a LED or torch (if your flash has it a modelling light works)to hit focus if youre struggling to hit sharp focus (specially with AF in low light) once you increase DOF, turn off light before flash fire and shoot. This photo has potential so i hope my info helps.
Cheers