Increase/Decrease Markers are a simple to use:

Pass your needle through the green ring when starting an increase row.  Pass your needle through the red ring when starting a decrease row.  Use the silver ring when the row you are starting is neither an increase nor a decrease.

Knitter's Increase/Decrease Row Marker: Swarovski Capri Blue $4.00	Knitter's Increase/Decrease Row Marker: Swarovski Hyacinth $4.00	Knitter's Increase/Decrease Row Marker: Blue and Red Millefiori $4.00	Knitter's Increase/Decrease Row Marker: Swarovski Fuchsia $4.00
Knitter's Increase/Decrease Row Marker: Swarovski Olivine $4.00	Knitter's Increase/Decrease Row Marker: Blushing Berry Bicone $4.00	Knitter's Increase/Decrease Row Marker: Light Aqua $4.00