What sort of conventions should you look for when analysing text types?

It varies depending on what the text type is. If it's an online piece, such as a blog entry, you'll want to note the significance of the wider reach of the text. Look for social media buttons, as well as hyperlinks to other places on the internet. Consider how this effects the purpose of the text. If you are asked to analyse a cartoon, make sure you comment on the pictures themselves not just the text. Just because you may not be an art student doesn't mean you can't analyse the position, symbolism and overall impact of visuals. Do be careful to only talk about literary devices such as enjambment, if you get a text type like poetry where it applies. Otherwise refer to it in more appropriate terms such as, syntax in this case.