Summary

Focus on what is right and helpful in your ideas, not on what is wrong with other people and their ideas.
Describe your better alternative, don't talk too much about what you dislike.
Talk about what you can do, and how we can encourage others to do what is needed, don't try to tell other people what they should do.

(This subject is also considered, from a slightly different perspective, in the article, A Fair Society.)

Details

What is Helpful?

If you want to make a helpful contribution, it can be helpful to remember 'TIP' - make sure it is True, Important and Personal.

True. You want to be able to present the evidence which says why this idea is true.
Important. You want to explain why this idea is important enough to give it your time and attention.
Personal. You want to be clear about the difference this idea should make to the way we live.

What Do You Want?

It is very easy to say what we don't like and what we don't want. It can be harder sometimes to say what we do like, and it is often very hard to say what we do want. But criticising other peoples' activities and ideas is a waste of time unless you can come up with a better alternative.

This is often the case with campaigning groups: we focus on the injustice we see, and wish to correct it. But we don't always think very clearly about what justice would look like - what the world would look like if our aim were fully achieved. Given the nature of the injustices we struggle against, it is easy to dismiss the question as irrelevant, as it is clear what we want to fix here and now; anything more can be dismissed as pie-in-the-sky wishful thinking.

But thinking about the end result is important. It has several benefits, both immediate and long-term.

Priorities. Being clear about the mission can help a group make appropriate and effective choices along the way.
Perspective. Over time, a discriminated-against group can become a group with some power, able to fight for its concerns against the competing concerns of other groups; the fight for justice in one generation can turn into the fight to defend entrenched rights in another generation.
Partners. Thinking about the end result can help us distinguish between those who are fighting alongside us for the same cause, and those who are fighting alongside us because our interests align at this point in time; revolutionaries can easily feel betrayed by those who fought with them at the start, but never shared the same goals.

What Can You Do?

Perhaps you can do nothing, beyond articulating what it is you are looking for - perhaps others will read and identify with it, and come up with plans.

But perhaps there is something small you can do? It won't achieve everything you are looking for, but it might move the world a tiny bit in the right directions. And maybe others can do the same, or use what you do as a starting point, to help them learn to do something better.

After all, it's better to light a candle - even a very small candle - than to curse the darkness.