Well laptops are complicated because they aren't really able to be "built or custom specification" to your needs.
However there are a lot of options to choose from regardless.
I recommend if you haven't already to get a price budget set it stone. A good point is usually < 1000$ or > 1000$.
Dependent on what you choose you can then proceed to see what you will need in regards to the computer. Is it for work, gaming, editing, etc. So you have basically narrowed down what you can afford, and what you need.
Now comes the part where you must find a site on which to purchase your laptop.
If you want general things in all categories go to Amazon.
Need something for work? Go to Dell (they also have Alienware laptops for gaming)
Need something strictly for gaming? Go to Acer or some other well known brand.
Basically just pick and choose what ya need.