How should I improve my chesstempo tactics rating? I was stuck on a chesstempo tactics rating of around1482-1509 for about 2 days. I reached my current level within 3 days. I want to improve to an 1800+ rating. How can I improve?
You should not obsess with ratings let alone tactics rating on some website. (Specifying your rating to the last digit suggests you do.) It is just a number. 


Once you solved a problem. Chesstempo also shows you the tactical motive for this particular problem which is quite useful for learning. Make sure that you can recognize each motive in the solution. If not, learn about this particular motive and do more tactics of that type of motive. It is essential that you take the time to understand the problem with the solution at hand.
Be patient when solving tactics. Don't go for the first good move you see. Consider all of your opponent's options. 
Do more tactics, but also mix it with playing regular games and resting time. The goal is to store those motifs subsconsciously and this can only be done by repition.