I was actually writing a text book on this material. Some people asked me for a copy and when I went to look at it... it seems that I lost it somewhere between machines (you'd think 20 odd years as a programmer would encourage me to make backups... :-P).

But very, very basic pointers: Free reading is actually the key. Read whatever you like. Read every day without exception. If the person is learning English, you're in luck because there are thousands and thousands of graded readers. Those are a great place to start.

Research has shown that you need to understand 95% of material before you can learn from context. This is massively important to understand. The advice of "If you don't understand it, skip over it and eventually you will understand" is well meaning, but is especially bad advice for learning a language which does not share a root as your native language. It can work well if you are learning French from English, for instance because the average English speaker knows something like 10,000 French loan words and can generally figure out what things mean from context. If you are going from Chinese to English, for example, you do not have that advantage.

When reading something above your level, scan the text for words that you don't understand. When you get to about 20, enter them into a spaced repetition program like Anki. Memorise them. Then re-read the text. The next day, re-read the text and get 20 new words. The next day, re-read both and get 20 new words. Keep doing this until the text at the beginning is as easy to read as your native language. Then start skipping that part. Every once in a while go back and read earlier chapters, etc.

Once you have read one book all the way through, find another book by the same author. They tend to use the same vocabulary and expressions from one book to another. You will almost certainly be able to read this book for pleasure without the need to look anything up. Switch to a different author for studying, but keep up the pleasure reading. Bootstrapping yourself to the point where you can read for pleasure is really important because it allows you to "study" without undue effort. For some reason, allowing your brain to relax is important for assimilating the information (at least in my experience). All work and no play makes for a person who is not fluent in the language.

As soon as possible, stop using dictionaries that translate from one language to the other. Instead, find a children's dictionary in your target language. Use that in Anki (yes, it's a royal PITA to enter definitions like that in Anki ;-) ). Also, if you wish to learn grammar, purchase a grammar text book for children in the target language and learn it exactly the way school children learn grammar.

For watching TV, keep a pad of paper next to you at all times. Whenever you hear a word you don't know, write it down (as best you can). Look up the words later. Start with children's shows. Watch them exactly like a 3 year old watches TV: "How on earth can you watch that same cartoon 500 times in a row?!?" In the same way as the book, as soon as one episode is as easy to watch as it would be in your native language, you will be able to watch the entire series for pleasure.

If you are very low level and you can't understand anything, use subtitles in your own language and watch for understanding. Once you've watched it a few times and have basically memorised it, watch it again with subtitles in the target language. This makes it easier to pick out phrases to study. Keep going like this.

Of course, it's easy to get bored with this stuff, so feel free to give up on a book/series for a while, or do something else. There really is an infinite amount of stuff to read/watch -- especially in English.

I won't really talk about how to read something to get information. This is really just scanning, but it's kind of an involved topic. I actually taught my students this so that they could game the university entrance exams. However, the main thing here is to get very, very good at question forms. Be able to convert between a question and and answer and back again. Then once you have a question, you should be able to locate the text that answers that question.

In a sibling message I described how to improve pronunciation.

I hope those things will help. One more thing you can do to really help your friend is to invite them to join you in as many normal events as possible. Take them out to the bar. Take them out to picnics. Especially when you have a group of friends going out, bring them along. For a long time they are likely to sit there in a corner and not say anything. It's important to tell them that this is completely OK. It's practically impossible to insert yourself into the conversation at first. Eventually it will happen though. Tell your other friends not to worry about whether the language learning friend is having a good time. Just keep including them on everything. This will help more than anything else you can do.