I think if it's hot enough that you're only going to want to wear two pieces (top with pants, shorts or skirt) or one piece (a dress) then the formula (assuming you've taken Angie lessons and have the clothing silouhettes down pat) is:
1) Statement jewelry
2) A great bag
3) Fab shoes
If you're not layering, then would go with at least 2 of the above, if not all 3.
For example, sometimes I just don't want to wear too much jewelry - it's too hot and sticky for anything more than simple stud earrings or a delicate necklace. So then the shoes and bag become that much more important.
And sometimes, my shoes may be less than interesting because I simply need comfort and practicality more than style; so then my bag and jewelry become that much more important.
Interest can be in the color, or it can be in the details. Colorful bags and shoes are big right now. Metallics too. But if you keep bags and shoes neutral, go for details.
For example a straw bag is all about adding texture - the color itself is neutral. Patent leather for sandals is big right now - patent would add detail even if the color is neutral. Or buckles or other hardware adds detail.
