What do you wear when the season is changing? HELP

How to stay cool and look hot in funky weather :)

"Doesn't matter, I'm hot...this doesn't apply to you, seriously dont' try it, you will look like a bag lady" - Kate Moss

When can you start full out wearing your fall and/or summer wardrobe?  I'm terrible at season transitions and these fall-summer hybrid outfits are making me feel schizophrenic.
 

Like, what are the rules to incorporating warmer clothing/less clothing, do you slowly introduce a scarf here or daisy dukes there OR do you have to fullout switch?  Like one day you just walk outside and proclaim "FROM THIS DAY FORTH IT IS SUMMER MOTHERFUCKERS"(while quietly shivering in your flip flops as the person passing you in a puffer jacket stares skeptically).
 

"Let summer commence ya'll!"

What are the Summer to Fall/Winter to Spring no-no's???

Is it okay to combine a....

• Sweater and Shorts?
• Shorts and Boots?
• Tank top, jeans, and boots?
• Scarf and tank top?
• Scarf and shorts?
• etc.

Give me your input!