At your speed, doing blind CROSS practice, and F2L practice (scramble cube do F2L and scramble again, over and over) can quickly take a few seconds of your average. Cross and F2L are the easiest parts to gain speed. I remember clearly doing 15 seconds over cross. That was when I was in the 1 minute range. Now I do cross plus 1F2L in 3 - 5 secs.. I never practiced speed on LL because I do not like spamming algs. When I repeat a PLL a few times, trying to make it faster, I tend to do other PLL's wrong since that last PLL that I practiced is becomming mussle memory for all my PLL's. LOL..