The most important thing for Greens to consider is that we will most likely only get one, two or three London Assembly members out of 25. There’s no room for colourful characters with narrow interests, bad tempers or a tendency for self indulgence. They need to be good communicators, both practical and radical, collegiate and disciplined.

We need to pick people who can get complicated and often innovative messages across to the mainstream media, to other politicians, to the public. It’s no use being Mr or Mrs Brains if you baffle people when you talk to them, or bore journalists with predictable soundbites. Politicians have staff to help with policy research and messaging, but nobody between them and their audience.

We rely on our Members to put across a good, rounded image of our party. Whatever your particular politics, will your choices show that the Green Party is both practical and radical, that we are able to achieve significant changes to Mayoral policy at the same time as advocating a radically different vision of London? Radical idealists might spend four wasted years making good speeches; practical realists might forget the reason they’re Green while working for minor concessions.

Our two/three members have, in the past, won a great many gains for London by working with other political parties and at times with the Mayor. The comparatively collegiate culture of the Assembly is one of the joys of working there. People who enjoy tribal politics, who thrive on factions and who find it difficult to work with others – especially if they’re those hated Lib Dems or “sell out” New Labourites, won’t get very far in the Assembly.

To focus on these basic political skills takes the final quality: discipline. Watching Caroline Lucas over the past few years, it’s been remarkable to see how hard she works to find realistic radical ideas, get them across to the public and the media in a compelling way, and work with NGOs, politicians across the political spectrum and anyone else willing to help her achieve our goals. To compare her to someone like George Galloway, who is an excellent speaker and fires a lot of people up, is to compare an effective small party politician to a character that can only be tolerated in a large party.

Of course this portrait of an effective small party politician reflects my politics; you may think we’re in this game for an entirely different reason. If you think there’s no progress without revolution or the Mayoralty, these reasons may not sway you.

It’s well worth actually watching the webcasts of a few Assembly meetings, perusing some committee reports and reading some press releases to get an idea of the work they do.

If you like the look of that work and can see its value, you might ask yourself: would this candidate be able to work cross-party on affordable housing funding and river deculverting, gain media coverage on these issues, and win some real gains for London?

I suspect I’m like the majority of people in that I really get put off by politicians saying “don’t vote for Party X or you’ll let Party Y in”, as though they’ve nothing more compelling to offer voters than “we’re not that lot”. Ultimately I would always want people to vote for the party they most support, give or take some tactical voting if they prefer. So if the Pirates are your bag then get involved with them.

But the Pirates are an unashamed single issue party. Their manifesto lays out a radical agenda for copyright, patents and online privacy. That’s an interesting proposition for an MEP who can take that militant approach in a very large Parliament. But MPs and councillors are constituency politicians, they need to represent and support people on every issue on the books with an open statement of their approach. If I were to vote for a Pirate, I’d want to know that they are concerned about the need for affordable homes, better partnership working to improve my town centre and urgent action on climate change. Even if I weren’t a committed Green, I’d want a local Pirate candidate to set her/his personal stall on those issues before they got my vote.

We Greens also have some good policy on these subjects, tying them into our wider approach to the economy, culture and government. When their grassroots and youth wing mobilise, the Lib Dems sometimes take these issues up, the Conservatives sometimes talk the talk and the split personality Labour government have made some good recent moves. I’d much rather vote for a candidate from a rounded party who also took the Pirates’ concerns seriously in these elections.

Caroline evoked a lovely analogy at the recent Compass conference to sum up the change in mood: we no longer need New Labour’s big tent to bring all progressives together. From now on, we should have a campsite of many small tents, cooperating to progress environmental and social justice, and competing where we disagree.

Maybe 2010 will be the year that the Lib Dems stop shamelessly lieing to undermine Labour and Green votes, and that Labour supporters – especially in publications like The Guardian and the New Statesman – relax their tribal obsession with The Labour Party?