One thing that really bugs me about iPad is that, apparently, you can't cursor around when typing things like this post. I'm hoping I'm wrong and just missing something and that some kind soul here will put me on the road to enlightenment. Please do it soon.
Of course, when you want to position the cursor in a piece of text using the on-screen keyboard (i.e. not a Bluetooth keyboard) the easiest way is to press and hold the screen at about the position where you want to position the cursor. After a second, a pop-up magnifying glass will appear that makes it much easier to precisely position the cursor - plus it also gives some options such as 'Select', 'Select All', 'Paste' etc.
If you 'Select' the word in which the cursor is positioned is selected and two vertical bars appear, one at either end of the word. With care (it takes a bit of practice) you can drag these vertical bars to select more text - either horizontally or vertically. Then you can copy or cut the selected text.
Tim