Useful tips in VIM Editore.

1. If you want to split the screen horizontally give command
:split
If you want to split the screen vertically give command
:vsplit
If you want to open an new/other exiting file in splited window give command
:new filename for horizontal window
:vnew filename for vertical window.
If you want to quit all window give command
:qall for quitting without saving the changes
:wqall for quitting with saving the changes
You can use normal quitting command for one particular splitted window like
q,wq
To move between the splitted window , use ctrl+ww

2. Folding techniques:
You can fold a block of code of a long file. The block can be anything like (),{},[]
or may be some code between the lines.
For example:
Suppose this is your code:
#include
.........................
.......
int main(void)
{
----
----
----
for(;;){

-----
-----
}
}

To fold the brackets {} of for loop, keep the cursor at opening bracket of the for loop and then use zfa} command. It will make a fold till the closing of the corresponding bracket. This technique also works form backward.
It means you can keep the cursor at the closing bracket and use command zfa{ .
For closing and opening the folds, move the cursor at the fold and use command za
If you want to fold the codes between particular lines , Use command
:beginning_line,closing_line fold
Give a space between closing line and fold command.You can also use fo instead of fold.

For more details about this folding option just visit the link.
http://www.linux.com/archive/feature/114138