I need help landing my first client

A common path is to start with family & friends. Can you find someone (e.g. friend of your parents) who has a small business without a website? Could be a bakery, or removal van or whatever.
Offer to build them a brochure website for a small fee. It's important to charge something, you're not doing this as a favor. But the main benefit is when you've done a good job, be sure to ask for a comment that you can stick onto your own website as your first client.
Rinse and repeat for your first few clients. Best of luck!

What about:

1. Spending 50% of your time bidding on projects on Upwork, etc. and

2. Spending 50% of your time creating a portfolio project to show potential clients the quality of your work and concentrate either on:

   a) Doing a website that is best-in-class for whatever type of client you really want to work with (e.g., if you love e-commerce do an e-commerce website or if you love advertising build a mock advertising company home page)

   b) Showcasing your skill in a new technology that is very in-demand right now (but only if it is something you really want to work on in the future) like Bubble or whatever...

The best route I know is to start small and keep working at it. Like wavehopper suggests, find a family member, friend, or friend of a friend that you can use to launch yourself into the industry. Put out a general offer on social media, and talk to people directly asking if they know anyone who needs a website. Don't underestimate the power of person-to-person relationships - I still get referrals from clients I made small websites for over 5 years ago. With every couple of new clients, your services will get better and more refined, and you'll be able to slowly bump up your rates.

An entrepheneur is someone who builds systems and innovates. Start early.

Build business systems that are scalable and replicable. Remember McDonalds, the fortune 500 company is run by teenagers such as yourself.

For you that means have a website process that you can follow every time.

Designing a winning website requires a well-thought-out online strategy focused on reaching organizational goals — that can be anything from attracting visitors to buy products to getting the public to understand an issue to introducing visitors to a new brand.

Also, try to have the client looking over your shoulder when you design. Either with a page builder or psd template. Saves countless revisions down the line.

Agree with what @wavehopper has said.
I just registered my first client for insteps.io and it was via contacts I already know. Start from people who you already know. That will help you become a pro and you will attract larger and richer clients. :)