Collocations for helpful - adj.

be, prove
consider sth, find sb/sth

extremely, fairly, very, etc.
enormously, especially, immensely, incredibly, most (esp. BrE), particularly
Thank you, you have been most helpful.

not at all, not particularly, not terribly
overly (esp. AmE)
genuinely
potentially

for
This information would be extremely helpful for teenagers.

in
Graphs are helpful in presenting the information.

on
He was very helpful on how to do the accounts.

to
The stairlift will be helpful to the older patients.

friendly and helpful
I found all the staff friendly and helpful.

Helpful is used with these nouns:
advice, comment, criticism, discussion, example, feedback, guidance, guide, guideline, hint, information, insight, introduction, leaflet, note, reminder, suggestion, tip