> Outline roles and/or skills wanted/needed.
> What kind of project it’ll be (assuming you now):
– Scope of project.
– 2D/3D, Genre, etc.
> Experience you’d want volunteers to have (if any).
Basically, you’re selling yourself in order to gain the favour of forum members by appealing to their interests, goals, individual skill-set, or curiosity. A lot of people fail to do this and therefore get minimum (if any) genuine responses (especially if you’re after more skilled developers).
In the future you should elaborate a little to maximise the probability of fellow developers, artists, or designers, taking interest in your proposal.