Reflective tape sounds good. I have a helmet light and wear gloves that are white on the back. I shine the light at my outstretched arm to light it up. With cooler weather I will be wearing a highly reflective jacket, bright yellow or orange, but actual reflective tape would enhance any hand signals.
Some kind of blinkers would seem ideal, but I use a rear flashing taillight so that could confuse the signal. The main thing is to let another road user (including cyclists) know why you are slowing or getting over to a left lane.
Be safe!