If you don't have one, the photostore probably has a lighted panel that you can inspect your slides on. However, the final pictures to be sent to Rodney, should be prints. If you can't do that then you might try an umbrella. Use an electronic flash if you have one. The bulb flashes give too much red colour bias to the photos.
Blue filters make yellow, orange, red and chartreuse look awful.
I haven't quite worked this out. I have a polarizing filter but it takes a lot of extra light and it's difficult to exclude red colouring. Camera supports Camera support, either a tripod or a monopod, will reduce trouble with blurring of pictures because of camera shake. Photographing the flower Look at the iris and find the imaginary line which divides the falls from the standards. Position your lens maybe 2 feet or 3 feet from this line and with the lens horizontal to the line.