Europe trip preparation: Inter-city travel

As part of planning, how do I get around plays a large part of how much things cost, where and how to get to and from accommodation, along with related activity relating to getting to and from there.

Taxis in London are obviously out for me.

Before I talk about intercity travel, I did take a look at getting to Paris from London via Train + ferry + Train combo as opposed to taking another plane or taking the more famous Eurostar. The cost seemed only marginally cheaper, though Eurostar might be cheaper if booked months in advance, but hey, we didn't even book the plane to Europe until less than a month to departure, and obviously I can't book a train with dates unknown. The big turndown was that, this route, meant that I could have possibly missed the last train into Paris after alighting the ferry at the France side of the English Channel. The town we would be stuck at seems like a small town with only a few hotels. We decided to take the Eurostar in the end.

Either way, how do I get around within those cities?

Well. The subways of course. Once I could figure out the unfamiliar names of the stations and the lines that is.

With all the discount tickets and such, figuring out what ticket is the most cost effective requires some advanced planning. Some cards are promoted to visitors can end up costing more (or very close at the very least) than normal fares. Those additional discounts they offer at select stores with that card? Ignore that: it's of stores/items that I'm not interested in, or the validity of the offer is in such a way that its easy to use it in an invalid period if you don't pay attention.

What is clear, however, is that using things like the Oyster Card (London) or buying tickets in sets of 10 (Paris) turns out to be cheaper than a single regular ticket.

Still have yet to figure out transport around Venice and, tenitively, Rome.