When you first approach a conference, assuming that they're interested, you can bring up any of the standard sponsorship requests as you would with any sponsor. However, there are a few unique areas where conferences can be a great source of support, more so than other types of sponsors.
Some conferences can be very expensive, others are free. If you can arrange for free entrance to the conference for participants, great! Discount? Still good! Just crunch the numbers and see if you can make up the difference with sponsorship funds.
If the conference is longer than 2-3 days (for example, EuroPython is 5 days + 2 sprint days), you might be able to get access to a room during the first day of the conference. Otherwise, the conference might be able to help you reserve space at/near the venue on the day before the conference begins.
This will help familiarize the participants with the venue, and if you time your breaks to coincide with the conference schedule, the participants will be able to mingle with conference attendees from the start!
More and more conferences are kicking off diversity activities, scholarships, mentoring programs, and more. If you aim for international attendance, you could approach the conference for help with travel funds and accommodation. It is worth keeping in mind that financial aid requirements can be larger for a conference workshop as people are often travelling from further away and staying for the whole event.
For example, many conferences already have room blocks or discounts at hotels, and might also be able to directly sponsor the rooms (or arrange for an invoice that another sponsor can pay directly to the hotel).
If you are partnering with a conference that already has a few hundred attendees, they should be able to arrange for a few dozen shirts, bags, nametags, lunch spots, etc. You can also ask to be connected with the conference sponsors for further support.
Note: coach shirts are better arranged separately, because then you can have control over the design, but shirts or nametags for participants that bear the conference logo are a great way to help the participants feel like they are a part of the bigger event, and it's not out of your workshop budget.
Conferences normally have a large-to-huge mailing list, countless followers on Twitter, and a social media strategist. You can therefore leverage their online presence to call out for coaches, sponsors, or even participants (as in "tell your women friends about us so they can come to the conference too!").
If you're organising a conference workshop, chances are you may not be living locally to the venue, and might not even see it before you arrive for the event yourself. It helps to have somebody local to help out if possible, or a conference organiser familiar with the location.
If you are ordering heavy or bulky swag (e.g. t-shirts, mugs, posters), depending on your transport options it may be easier to have those sent straight to the venue - ask conference organisers whether this is possible. This may mean you don't see these items until you arrive so it can help if somebody local can receive them and check that everything came out OK!
If you can secure a Django Girls lightning talk, they're a great way to introduce conference attendees to the project and broadcast a call to action. Check out the resources repository on GitHub for presentation templates!
A sprint/hackfest is a great way to give participants the space to continue to work on their websites, extend it, edit the tutorial, or simply learn more Django or Python!
If the conference is Python/Django-focused, you can probably join an existing sprint room where core developers are already working. Otherwise, you can announce the sprint/hackfest as a general Django/Python event and invite core developers or other interested parties who want to learn or work on Python/Django.