FIRST macro ever with my new Sigma 150

you'll find life much easier with flash especially with what is quite a heavy lens. It is razor sharp but has to be kept rock steady. Butterfly shot is fun.

it doesnt seem like this lens is as heavy as I was expecting.
My 20-200 feels more but its only 1.56lb and this sigma is supposed to be 2.1lb

Here's another few cents worth... I've found if you use a ttl metered flash you can use manual mode (exposure that is - not focus) set to pretty much anything and the flash will compensate for any lack of light. This way you can stop down the aperture to get more DOF (and get a bit of relief from bad focus - those critters just never want to sit still). You need to be careful about how you aim the flash with harshness of lighting etc, but most of the time it gives a decent shot... experiment.