Slow down! – your breaking distance is going to multiply. Keep a safe distance and slow down!
Skip puddles! – you never know what is at the bottom of a puddle. It is collecting water for a reason. It might be harmless or it might be glass or a pothole. Avoid them!
Shine! – in the rain, more than ever, you need to shine. Use your lights, wear your reflective gear and be extra-visible.
The big clear umbrella will help. But slap some cool reflective stickers on it like this Glow Kitty. Lots of options are out there, Google reflective bike stickers and make a statement!