A score of 670 is pretty achievable. Once you are done with concepts, I personally think that you need around 45 days of quality practice 4 hours everyday. On weekends, try extending study hours.
Start practicing with the clock. It is the only thing which works. I have personally seen drastic improvement in my timing once i started using the clock. Always have an exit strategy for every question. You may solve some questions in lesser time - however, keep it a thumb rule that you WILL NEVER spend more than 2.5 mins on a quant question. Remember, in quant, every question can be solved under 2-2.5 mins. If you are struggling, you might want to change your approach to solving questions - this is actually quite crucial - a friend of mine started scribbling to arrive at the answer and this saved around 20 seconds every question.
With verbal, the only thing which helps with timing is Practice. Generally, I aim to solve SC questions faster to make up for time in RC and CR.
Practicing under timed conditions is the only thing that helps.