Please check

[Anonymous]

He is the leader of/for the democratic party.

Development steps for/of the windows forms.

Please clarify my doubts around the of/for

Thanks in advance

[Anonymous]

http://dictionary.cambridge.org/results.asp?searchword=of&image.x=33&image.y=4

http://dictionary.cambridge.org/results.asp?searchword=for&image.x=16&image.y=8

These 2 links should help you to get started.