I have been using vim for quite some time and am aware that selecting blocks of text in visual mode is as simple as SHIFT+V and moving the arrow key up or
In addition to what others have said, you can also expand your selection using pattern searches.
For example, v/foo will select from your current position to the next instance of "foo." If you actually wanted to expand to the next instance of "foo," on line 35, for example, just press n to expand selection to the next instance, and so on.
I don't often do it, but I know that some people use marks extensively to make visual selections. For example, if I'm on line 5 and I want to select to line 35, I might press ma to place mark a on line 5, then :35 to move to line 35. Shift + v to enter linewise visual mode, and finally `a to select back to mark a.