The campaigner of today would not be able to get away with the explicit xenophobia, if not racism, of some of the Conservative posters, but the strategy of appealing to the ordinary voter's fears has not changed. Interesting that the term "radical" which is now a badge of honour (unless applied to Islam, of course) occupied the same place in Edwardian Britain as "liberal" does in US politics nowadays. The Liberal posters hammer the theme of free trade, and its benefits for the pockets of ordinary people, but there are also attacks on privilege and the hold the established church still held over schools. Then there are the promises of old-age pensions and cuts in income tax for wage-earners (both delivered, I believe) in this poster which were echoed in 2010.
If you don't recognise the personalities depicted in the cartoons (and surely only political history anoraks will), there are helpful notes. I think the compilers missed one reference, though: in the Unionist cartoon attacking Campbell-Bannerman's gardening skills, the title appears to be a reference to a music-hall song made popular by Gus Elen at the end of the 19th century:
Oh! it really is a wery pretty garden And Chingford to the Eastward could be seen Wiv a ladder and some glasses You could see to 'Ackney Marshes If it wasn't for the 'ouses in between