First, like any presentation think about what your key message is. You don’t have a lot of space so consider if each tweet will be a standalone message (good for retweets) or if the whole set needs to be read to make sense of your argument (allows greater depth). Either way make sure you number your tweets to help people follow along. You might also want to thread your tweets (reply to yourself) so that everything is in one place.
What do you want from the event? If it’s networking, try to be present for as much of the day as you can so you can engage with other talks as well as with people reaching out to you. If it’s too share knowledge, consider using extra hashtags to draw in tweeps who aren’t following #pressed19. Boost engagement by using gifs and images.
Scheduled tweets – if you’ve not used a scheduler before, be aware that some of the free accounts give you a limited number of tweets – this might not be enough for your whole presentation and can cut you off mid flow!
Times – use https://time.is to check what time you’re presenting if you’re not on GMT
And after the event, think about using twitter’s ‘moment’ feature to gather all your tweets and maybe some of the replies into one place for people who weren’t able to follow along live.