Had a near miss a few years ago because I forgot to cancell my blinker (indicator) after a previous turn. It was all my fault as the driver thought I was making a turn because my blinker was still on. To this day I`m forvever checking and triple checking to see if my blinker is off, to a point that it is a bad habit and drives me crazy. I still occasionally forget to turn them off then realise it a short time later and this exasibates the annoying need of constantly checking that the blinker is cancelled.
Other than fitting a larger flashing light or a buzzer any other suggestions?

A competent electrician could wire in a microswitch or so near the headstock that switches the indicators off after going straight or so for 10 seconds.
Since you are paranoid about it you probably never forget it agian, it is up to you to decide if you need it since it would be hard to set it up so it works properly. A beeping thing on the other hand is possibly the easiest, one might think a forklift is reversing or so.....
An electronics guru could possibly figure something out that cancels the indicators at a certain speed.

While I'm typing the idea pops up to use the 2 nd or 3rd gear switch on the gear box to reset the indicators, this might work too and the wiring etc. is there to use.

I've never installed a Kisan self-canceling relay , but I have used their headlamp and tail-lamp modulators and they
install easily and work flawlessly

Kuerbis

I quite often forget to turn off my indicators as well and could use something like that bit pricey though.

I know,
sell your SD and buy a HONDA Goldwing, they have self cancelling indicators fitted standard!

i feel your pain. My touring bike has auto shut off and it's great. I hop on the SD and look like a tool riding around for miles with the blinker on.

Bad ass looking motorcycle + Bad ass sounding motorcycle + blinker on for miles = Dumb ass

my 65 year old neighbour fitted bigger, brighter flashing lights on the dash to indicate indicating.

worked for him....

Going to fit a cheap little buzzer and wire in with the indicator light in the dash.

yeah i suck at turning them off, but always just hit em at random in case there on.
my alpinestars felt funny around the right thumb area so i looked closely at them and there was a hole worn right thru!!! im like what the hell, they were only a couple of seasons old.
my buddy said it was from the directionals, so now i have a sweet duct tape repair till the new ones come in! i loved those gloves too...