df <- data.frame(x=1:10,group=c(rep("a",5),rep("b",5)))
legend_title <- "OMG My Title"
ggplot(df, aes(x=x, fill=group)) + geom_density(alpha=.3) +
scale_fill_manual(legend_title,values=c("orange","red"))
p <- ggplot(df, aes(x=rating, fill=cond)) +
geom_density(alpha=.3) +
xlab("NEW RATING TITLE") +
ylab("NEW DENSITY TITLE")
p <- p + guides(fill=guide_legend(title="New Legend Title"))