I recently heard about the rule of thirds on a youtube channel.  I was quite dubious when looking at it at first.  But guess what, it really does work.

Ok am tall and have long legs but it will still work on me.

You divide your body into thirds to make your torso look smaller and your legs longer.  You want essentially a third for the top half of your body and 3 thirds for the bottom.  As you can see in this picture I look like my legs are very long.  The reason is, same colour boots as jeans to elongate the legs and a stark contrast in colour from the top of the body to the bottom.  A "V" neck will also work as it shows more skin and it draws the eye to where the V ends and the waist area begins.

Rolling up the sleeves to 3/4 of the arm will work too as it shows a definite end to the top half of the body.

 See how my legs look shorter here, I am wearing a jacket the same colour as my pants and different coloured boots.

It looks like my legs are the same length as my torso.

The sleeves are full length and a contrasting colour to my top as well as by my sides making my arms look very long  which doesn't help.

In this picture my legs look slightly longer but my arms are still long as I am wearing full length sleeves.

I am also still wearing a contrast coloured boot so my legs could actually look longer with a black boot

My legs look much longer here due to the boots being the same colour as my pants.  My sleeves are also now 3/4 sleeves which end at my waist making it more defined so my legs look much longer and torso shorter.