This may sound pretty general, but get good CO2 (even DIY helps), keep your lights and ferts in check, and possibly dose with Seachem Flourish Excel to help prevent the algae from coming back...
... but to remove it manually, try a comb. Remove as much as you can by hand, then take preventative measures.
... but to remove it manually, try a comb. Remove as much as you can by hand, then take preventative measures.