Best way to "downsize" images in LR4

[Scarpz13]

Hi Everyone
I use Lightroom 4 for my basic workflow & editing... and when exporting to Jpeg I typically use 100% quality and leave it at that, great for viewing on PC or printing.
However if I want to email photos to relatives, or upload them, these files are WAY too big.
Can anyone tell me what is the best way to "shrink" the file size while minimizing image quality loss?
should I
A) reduce pics to say 2 MP and still save at 100% quality?
B) leave the MP (in this case 22), but save at say 20% quality?
C) some better way I havent figured out!

I am trying to get files around 500k or so... at the very least under a megabyte.

thanks!

[RS2021]

One way is when you export, in the export dialog box, midway down, you have an option to specify the final size of the file desired.