Megan Stewart: High search volume and low competition. You want lots of people searching for it each month and not a lot of competition
Ammon Johns: The search volumes only really matter if somehow every visit turns magically into cash, such as you have advertising income on the pages based on impressions.
Not all searches are alike. Google have spent the past decade working on better interpreting the *intention* behind each search, and changing their entire algorithms around it, because it is THAT important.
So, the most important aspect of the keywords you choose is whether or not they convert into customers. Whether that specific way of phrasing their needs makes them a better or worse prospect than another similar way.
There are people with this whole `free traffic` mentality. The idea that even visits from people who were never, ever, going to be remotely interested in a product or service have no cost, and therefore should be targeted. Such people are idiots.
You`ve been a user of the web. Your time has value. When a site wastes your time, especially from a search result, you carry away a negative experience, both of the search engine, and of the site/brand. Just hours or days later, you`ll have forgotten the specific search terms used, and all you`ll remember, going forward is "Oh, I saw that brand before, they didn`t have what I wanted", or even more simply "Oh that brand again, they were crap and disappointing".
Think of the immense stupidity it would take for anyone to actively work to maximise those negative brand experiences.
So, when you are working out the keywords to focus on, the absolute most important thing is whether those searchers will convert for you. Because the ones that don`t, that buy from someone else, always remember that your competitor was `better` than you. If they hear a friend talking about maybe buying from you, they tell them to try the competitor instead.
You`ll never, ever, get a 100% conversion rate from search, but if your conversion rate is below 1% of visits, you may very well be making far more negative brand experiences than positive ones, and having invested time, effort, and money to do so.
Jeff Ferguson: The standard strategy is to shoot for high volume/low competition, but that isn`t always possible/realistic. More important is to have a realistic view of volume versus other important keywords for your industry. What you might see as "low" might be a goldmine for some industries. Finally, remember that volume is a directional number; don`t get too caught up on accuracy here. The idea is to give you an idea if the term is worth your time, not calculating complex estimates.
HS Kohli: you should go for less competition kw initially but if you do not have any budget constraints then you should definitely go for higher competition keywords.
Christine Hansen: I wouldn`t opt out on broad keywords in other languages (than English). I would do a mix. So many (low) keywords with absolutely no data eg close to zero searches.
Should I rather go with keywords with high search volumes but also higher competition or a with less competition and search volumes? 
