Referring to the original post, I think that the real problem, as many have stated, is that you take too long to form your cross.
Get cross blindfolded DOWN PAT before you move on. Take as long of a time as you need to inspect for this--it's not easy when you first start out. Over time, your inspection will get shorter as you become familiar with visualizing the cross quickly.
I do NOT suggest cross on D, considering I never got accustomed to it. I am a fixed cross user, so I solve cross on only one colour. In my case, this is white. However, I solve white cross with the white centre on any side, wherever it's easiest to solve quickly and efficiently. Usually, I end up solving cross on F. However, you can do what you wish.
Then, if you want to learn CFOP (aka Fridrich, if you are unaware--a lot of slower/beginner cubers are), I suggest working LOADS on your F2L. Even if you drill F2L for an hour on end, it'll really help. Get used to the basic cases. For the more difficult cases, I suggest seeing
Jason Baum's F2L site and checking out his algs. Don't memorize them, though. Follow the algorithm and see what it does. The majority of F2L cases are just breaking up, pairing, and inserting with simple 3-or-4-move triggers with U turns in between.
Now for last layer stuff:
If you don't know it already, I suggest learning 2-look OLL and 2-look PLL.
My post on two look OLL.
2-look PLL can be found on the wiki.