Books, Newspapers and Magazines
The first place to look for English language newspapers and magazines is always the local railway station. Not every railway station has a newsagents but, in my experience, all of the ones that do sell at least the English language European edition of the Financial Times. Most of them sell a range of other English newspapers and the larger ones have American papers as well.
The availability of English magazines in these places is more varied and is often restricted to the small number of titles that are of interest to locals. So you might find a British classic car magazine but not Autosport as a local wanting to read about F1 racing would read one of the German titles.
Imported magazines are very expensive in Germany. They seem to be between 60 and 100 percent more expensive that they are in Belgium so it is not just the cost of importing them.
Many railway stations also have a bookshop and these often have a small section of English language books. In these shops, the selection of titles is normally geared to an English readership and is similar to that which you might find in a branch of WHS in an English railway station.
Most of what I have said about Railway Stations is also true for Airports.
If you are near to anywhere that has a British Army base, it is worth checking to see if they have an outlet for books, newspapers and magazines. Some of these are restricted to Army personnel but others are open. For example, in Paderborn, you can buy the English editions of all of the normal British newspapers on the same day from the YMCA!
You will find some English books in many other bookshops but the selection is more likely to be geared to Germans who have an interest in the English language. So, you will find mostly fiction that might appeal to a person learning English or technical computer books.
Some towns also have a specialist English bookshop.
English language computer books are often a good buy. They are normally imported from the US and they are sold at the US price with an importers mark up which means that they are often cheaper than they would be in the UK! That is rarely the case for other books. Unless you are lucky to find a shop with stock that was imported when the pound was down at DeM2.20, you will rarely find any bargains.
In my experience, the best place to buy English books in Germany is from Amazon. I prefer to use the .com and .co.uk sites and so I cannot comment on the .de site but I regularly place orders with Amazon in the UK and US and have never had any problem with deliveries. The UK site appears to add VAT to German shipments. The US site does not and, two years ago, I was normally made to pay about five Marks per parcel for the VAT but recently, the Germans seem to have given up asking for this.
The only English books that I buy here now are computer books when I need them faster than Amazon can ship them to me.
Newspapers by Subscription
In some parts of Germany, you can get the FT delivered each day. This is organised nationally by the FT but the quality of delivery varies.
In Ulm, I was able to have the paper delivered each day with few problems. Over a couple of years, only a handful of issues failed to arrive.
In Paderborn, despite the fact that I was living in the town centre, the FT refused to deliver. What was really annoying was the fact that, I wrote to them and asked to have my subscription redirected there from Ulm. They never said "no, we cannot" they just stopped sending it and never contacted me. Finally, when I contacted them, they said that my apartment did not exist. This was odd as they had the correct address and, when they finally agreed to refund the rest of the subscription, they happily posted the cheque to the non existant address. Of course, I received it and cashed it.
Subscribing to Magazines
This should be entirely normal and routine but there are odd problems. When I had a subscription to Autosport, about 15% of the issues just never arrived!
Once, my subscription to Private Eye was stopped because the post office returned the copies to the magazine as undeliverable.
In both cases, the magazines were packed in transparent plastic bags. Other magazines that are sent in the classic "plain brown paper envelope" arrive with no problems. Just to stop the sniggering, the magazines in envelopes are things like "Flyer" the UK General Aviation magazine.