I tried to replace light in harbor breeze light. I broke globe, and had to take out 3 tiny screws to get inside the mess. I keep dropping them. Tried tweezers to hold, while you stand there trying not to fall off ladder. I can't believe they are so tiny. Any help appreciated.

Im not sure how small these screws are, but I have used Vaseline on the tip of the screw driver. Kind of holds the screws.

You can also magnetize the tip of your screwdriver... :D

Also, you can pick up screw starters (they are push clamps). You insert one into the slot and then push down on the barrell and the starter top spreads out to clamp the slot.

Also magnatized screw tips.

Or start the screws without the Globe, when all three are started Install globe and tighten.

Stratmando is correct, you need to start each screw into the fixture by just just a thread or two and then slide the globe into place.

For holding flathead screws a couple of other methods is a dab of "Slipstick" on screwhead, or fold a piece of paper over tip of screwdriver and force on screw.
Slipstick works on Phillips and Stainless screws also.

Are they thumbscrews?

I use strat's method usually. All the suggestions are good ones.