If you are learning or planning for on page optimization, then creating effective website URL will not only help your content to index easily, but improves your organic ranking, improves conversions and avoid duplicate content.
So we need to follow the best practices for URL structure to create user friendly url and avoid duplicate content issues.
URL has same importance as writing effective Title and Meta descriptions for any website.
So guys if you are building a fresh website with Asp.net , Java or PHP I suggest that you follow some guidelines for creating best URL architecture for your website.
For Best URL structures, I Suggest you that you should avoid port numbers and query parameter. Have some parameter in eCommerce website create duplicate content.
Architecture of URL

URL Structure Recommendation
Generally when I planning for URL structure I always follow

Domain with partial match keywords
Your directory must contain targeted root keywords
In sub category you can target secondary keywords of your directory.
Avoid Query parameters
Short URL maximum 100 characters
I redirect my http://www.example.com to http://example.com (www itself search engine consider a subdomain, and Sub domain has separate value)
Now after SSL updates follow https
Well if you follow this structures I am sure you have done your 10% of SEO work, and step by step you can easily achieve the 70%+ on page optimization. If you have any good suggestions or doubts please left comment, I will surely try to find solutions for it and revert you back.