You should only follow links in emails you ARE EXPECTING, or ones which are clearly relevant to you and give plenty of references within the text of the email that they are for you (so they have your actual name, not just a "dear sir")(they have details relating to something specific to your circumstances, "about your recent of order of (product you actually bought)").
You should NEVER follow links from emails which are from companies or organisations with which you have had no previous contact, these are almost always scams. Especially if the email is designed to scare you into urgent action, or to tempt you with the promise of vast sums of money, or contains spelling and grammatical errors.
You should also always check the exact email address that the email came from and make sure it sounds right, big companies will not use something similar to their name as the domain, they will use their actual name as the domain.
As a general rule support@[company].com probably belongs to the company but support@[company]supportfree.com could belong to anyone.
You can also use features in your webmail browser interface or email program to see the full original text of the message, this shows a list of all the servers it has passed through from sender to you, do any of them seem like somewhere which an email from a company shouldn't have gone through?
You should also always hover your cursor over the link, and look at the area in the bottom right hand corner of your screen to see where it is going, if the email is from a company you know and the link goes to a page on the company's official website that is generally safe, but if it goes to a bit.ly (or other link shortening service) link, or to some link with a very messy and unusual domain name then it is suspicious.
As an extra measure running a script blocker (like NoScript) and an antiexploit program (like malwarebytes anti-exploit) provide you with drive-by blocking protections if you follow a link which fits all the safety criteria explained above but still turns out to be malicious.
In the end, think of links like attachments, they have just the same potential for carrying infections, infact arguably they have MORE ability to carry infections because while most people know attachments can hold viruses many people do not realise that browsers where scripts and plugins are free to run automatically can be exploited.
If you set yourself a personal rule of "I will only follow links from emails which seem safe enough that, had these emails got attachemnts instead of links, I would feel safe opening such attachments" you should be alright.
Edited by rp88, 19 July 2015 - 01:33 PM.
Back on this site, for a while anyway, been so busy the last year.
My systems:2 laptops, intel i3 processors, windows 8.1 installed on the hard-drive and linux mint 17.3 MATE installed to USB