Believe it or not, the best way to do pullups is to actually do
pullups. Get someone to assist you for the first few. Your arms
will ache like hell, but you're on the way there.
If no equipments available, I find doing pushups does help to a
certain extend. But doing 10 pushups wouldn't help, >40 works.
If still cannot do pullups, nevermind, at least the upper body
looks good.
