Use partitioning chromatography, by changing the polar to non polar solvents, or from less polar to high polar. In general prepare aqueous extract and partition it with methanol, then you can go for ethanol only absolute.
if it is leaf ensure extraction of chlorophyll first then follow Ravi suggested most time before getting to this polar solvents the chlorophyll might have been extracted with the polar solvent. So i will advise you start from non polar to polar.
Serial extraction with soxhlet method using solvent of different polarity. viz. Hexane, chloroform, methanol/ethanol. methanol/ethanol-water (1:1). etc. the same sample 1st extracted with hexane, then chloroform, then methanol/ ethanol and so on.
For high yield you can used Ultrasonication and microwave assisted extraction or super critical fluid extraction with similar way as state above.