Hackers and scammers are excellent at disguising themselves, and portraying the face of a legitimate website. Don’t get lost in the bright colors and nice designs, but read properly the website and look for suspicious material.
 

Every genuine website should have a decent Contact Us/About Us section that gives you enough information about the address of the company, phone number, and legitimate email address.
Go ahead and try to call the website, it will give you peace of mind to hear the person answer you.
Be skeptical with a @hotmail, @gmail, or @outlook email address.
Most fraud website will have no phone number, no address; and the only contact method is a form that you write and submit on their site =  no trace and proof of contact.

Where is the website located? Some countries host more scammers that others, like:
Russia
Ukraine
Africa
China (unless you are dealing with the big trusted names such as Taobao, Alibaba, AliExpress, etc).

Secure payment methods such as Visa/MasterCard or PayPal guarantee a protected transaction between the buyer and the seller, and is traceable in case of a problem later on.
Fraud sellers will attempt to receive payments though expensive Cash Transfers, like Western Union/MoneyGram, which destroys any ability to track and trace the money sent to an unknown person.
Wire Transfers on the other hand are credible, as long as the beneficiary is the real company’s bank account or a trusted party.

A secure link better be present when paying and using your credit/debit card. You know it is a secure link by seeing the S at the start of a link: https://www.example.com

Chrome and other browsers recently started focusing on the missing secure certificate when vising a website. That’s the S  that starts at the beginning of any link after http.
 
Absence of a secure link does not mean the website is not trusty or unsecure, many known companies around the world do not yet have secure certificates and you can deal with them. 
Many trusted website show their products and their services, without selling online and without payment gateways, so they do not need the secure links.
Analyze their website and proof of contact details. As long as you are not sharing any sensitive info with them, like your password or credit card.

One day, we got fooled when buying from True Religion Jeans. 
The websites seemed authentic at first glance, so we happily purchased and paid for 2 jeans. Then, we get an SMS saying the card was charged in CNY (Chinese Currency). Upon reviewing for a second time, we found out their domain name was www.truereligion.us.com and not www.truereligion.com
The www.brandname.xxx.com triggered it, as it’s a third party passing off as the original brand.
Lesson of the day: Read properly the website’s name, as a real brand owner will not have a sub hosting service or third party domain name.

Seller reviews and product reviews:
Many platforms such as eBay, Amazon show you the seller’s reviews, location and data. Read what other people like you have to say about the product itself.
Tip: A recently opened seller’s account, with no reviews should be avoided. You should know what you are buying and whom you are buying it from.


Search Google for reviews:
For example, write on Google:  “reviews on truereligion.us.com” and read the blogs and forums discussing this website; you will see what others say about their experience. Third party pubilc open forums is a good read.
On the other hand, reading the reviews on the website’s own Facebook or Google profile page does not always tell you the truth, as they might be fabricated. 


Scan Advisers and other tools:
In addition to the tips and tricks provided above, you can resort to tools such as https://www.scamadviser.com/ and https://www.trustpilot.com/ 
While this is only a guideline and based on computer stats, it does not reflect the facts on the website owners. For example, Latvia domain names (.lv) are considered high risk countries by internet providers, simply due to statistics. This does not mean the website you are looking is a fraud, there are many recommended and trust-worthy websites in Latvia to deal with.