What makes a good portfolio? Or how do I know how I can proportion my investment portfolio?

A good portfolio should be

1) Well diversified - between asset types as well as geographically. I believe an ideal portfolio should include a percentage of bonds, depending on your time horizon. Without knowing more information about your situation, an example portfolio of someone with a long time horizon(~30 years), would be looking at an asset allocation of approx 80% stocks 20% bonds with the stocks portion being diversified globally as well.

2) Low cost - you can’t guarantee your returns, but you can keep your fees low by choosing your brokers/investment vehicles properly.

3) Simple to follow - I can’t stress this enough, for most people, investing isn’t our full time job, there shouldn’t be a need to spend hours poring over financial data. Stick to a simple, well diversified and easily followed portfolio which you can make contributions to regularly.

A good portfolio is one that recognises the risk you need to take or avoid to achieve your goals. One that is diversified across geographies, industries, and asset classes.

If you're investing for 5 years vs for 50, your portfolio will look extremely different.

There are many ways to consider risk strategies. I have an ABCD framework, others may have theirs. If you need advice, work with a financial advisor. Either a human or a digital one.