Water droplets may appear on garments when you have been steam ironing for a while. This happens because steam has condensed on the ironing board. 
Dry the wet spots on the garment and the ironing board cover by passing the iron over them without pressing the steam trigger. If the underside of the ironing board is wet, wipe it dry. Make sure you use a mesh-top ironing board with a thick felt material.

This minimizes steam condensation on the ironing board. 

When possible, select a lower steam setting or use less steam during ironing. Use steam ironing during the first few strokes of the iron across the garment, then release the steam trigger and finish up with dry-ironing strokes. Replace the ironing board cover if the sponge material has worn out. You can also put an extra layer of felt between the ironing board and the ironing board cover to minimize condensation on the ironing board