Some helpful suggestions for drawing trees with the program

I've starting using that online program to generate the trees. I have what I think are some helpful suggestions.

Firstly, to generate triangles under an NP where you do not want to draw the internal structure - this will happen automatically if you do not use brackets and have more than one element. What if you have a single word, like How_i? I would suggest is use the period beforehand. Thus:
. How_i

[NP . How_i]

Secondly, since these labelled brackets get out of control, since there are so many of them, I strongly suggest you use indentation to make things clearer. This is the standard strategy used by computer programmers. Thus, without giving away too much of the homework, the top of my labelled brackets looks something like this:

[CP [NP . How_i]
    [C' [C  [did_x] ]
        [IP [NP . John]
            [I' [I t_x]
                VP
            ]
        ]  
    ]
]

which looks much better than
[CP [NP . How_i] [C' [C [did_x] ] [IP [NP . John] [I' [I t_x] VP ] ] ]]

in the indented example, the end bracket is aligned with the opening bracket, the first daughter of a node is placed on the same line as the mother, and the second child is placed on the next line, indented over so that it is aligned with its sibling.

Using this methodology should make the act of writing and understanding labelled brackets much simpler and error-prone.