In last contest, i reached specialist. It took around 2 years for me to get there. But I want to reach expert with in next 6 months.

I can solve 1500 rated problems with 1 hour. I have good hands on basic ds & algos & stl. Also I can solve graph problems <=1800 rated, but I can not solve dp problems.

Now which topics i should learn? What should be my way of practicing? Till which problem i should solve in contest to reach 1600? If you are a Expert, please suggest me that helped you to reach Expert from Specialist.