Terms like strategies, cognition, metacognition, or self-regulation might sound like something too scientific. But the truth is, we already apply these in our everyday lives. And so do our children. We just don't call them these fancy science names.

Introduction to Strategies

So, when you say that you've forgotten your password and keep repeating the new one to remember it- you are talking about cognitive strategies - memory strategies, to be specific. When your child says that they can't find the keywords in the lesson, it's another type of cognitive strategies - the so-called organisation strategies. 
When you realise that you have to change your plan or focus on different goals if you want to finish the presentation for your boss - it's metacognition and self-regulation. Just like when your child recognises that they can't focus anymore and need to take a break. These are all strategies - actions we take to do something.
And learning strategies are simply ways in which we learn something.  
When we talk about learning strategies, we usually have in mind cognitive and metacognitive. 

Cognitive Strategies

Today, we'll find out something more about cognitive strategies.

The term "cognitive strategies" means the use of the mind (cognition) to solve a problem or complete a task. 
Some of these are repetition, elaboration, organisation, and integrative strategies (1). 

Should parents teach their children these strategies?

Well, if we talk about explicit teaching, where you explain how and why we use these strategies and then give them tasks to practise - no. But, if you mean to show them, give them examples of your own learning (learning is not only what children do in schools, grown-ups also learn), then - yes!

Repetition

Have you, or your child, ever gotten a test result, not the best one, and you thought to yourself, "I would've done better if I'd just gone over the material more times." Well, guess what - the result would've probably been the same. Reading something over and over just won't make the information stick.

If you want to remember something, you have to be engaged, put in some cognitive effort. It isn't the repetition of studying that yields positive results. The cognitive effort exerted during that studying is what appears to matter. So, if you see your child reading the same text for the tenth time and still can't remember what they've just read, suggest another strategy, a higher-level strategy like:

Elaboration

These strategies can help your child store the new information in their mind by making links between them. So, if you see your child struggling with memorising or understanding the lesson they have to learn, encourage them to write a summary. Using this summary, they can retell the whole lesson. If they are not fond of writing too much, note-taking is another helpful technique. They can use pictures or words. And because I like colour coding, I would always encourage my learners and my kids to organise pieces of information by colour.

This leads us to.... 

Organisation Strategies

Like the previous, these are also higher-level strategies that help to build connections among ideas. My favourite is making mind maps. You can make them before studying, to see where your thoughts take you and find the ideas you'd like to investigate. You can include any new associations from the different concepts. I used to make them as a tool for revision after I have read the text. Besides mind maps, you can encourage your child to underline or copy the most important words in the lesson. So-called keywords. The thing with finding the keywords is that this skill develops a bit later. Younger children have difficulties distinguishing between less and more important information. So, developing this skill takes time. But, you can always work on this - use the reading time in the evening and ask the child to tell you the three most important words from the book (or five, or one, depending on the book). Then, talk about it. Ask them to explain why they chose those words. Tell them what you think is important.

Integrative Strategies

Simply put, using these strategies, your child brings together prior knowledge and experiences to support new knowledge and experiences. You can practise these as you organise a movie night. Ask them if they already know something about Madagascar (if you're watching Madagascar), what animals live there, where is it on the map, is it hot or cold there... You can do the same when you travel. Have you ever been there? Do you know anyone who lives in that country/place? 
And finally, you can ask your child similar questions about the lesson they have to learn - do you already know something about this topic? Have you mentioned similar things in other school subjects? 

So, helping your child develop some of these cognitive strategies is not that difficult, is it? Just talk with them, encourage them to think and get engaged. Use questions, give them examples, and be enthusiastic about their learning.

Suggested reading on the topic:

(1) You can read more in:

Weinstein, C. E. & Mazer, R. E. (1986). The teaching of learning strategies. U: Wittrock M. (ur.), Handbook of research on teaching (315-327). New York: Springer Verlag.

Taz, B. (2013). Elaboration and organization strategies used by prospective class teachers while studying social studies education textbooks. Egitim Arastirmalari-Euroasian Journal of Educational Research, 51, 229-252.

Lončarić, D. (2014). Motivacija i strategije samoregulacije učenja: teorija, mjerenje i primjena. Učiteljski fakultet u Rijeci