I've been very fortunate in 2024 so far, with my personal ASX share portfolio up around 30% since the start of the year. It's a very pleasing return to be sure, given that the S&P/ASX 200 Index (ASX: XJO) is up around 5.8%, and the S&P 500 Index (SP: .INX) has jumped by roughly 24%.

Even though I didn't quite get to the numbers that my Fool colleague James did, I am nonetheless very stoked to see such growth in my investments.

I invest extensively in both ASX and American shares. Both markets have provided my portfolio with some big wins.

In the US market, my positions in Tesla, Meta Platforms, Alphabet, and Duolingo have been particularly lucrative.

Closer to home, some of my best-performing ASX shares include MFF Capital Investments Ltd (ASX: MFF), Wesfarmers Ltd (ASX: WES), and National Australia Bank Ltd (ASX: NAB).

But now that 2024 is almost over, and 2025 is fast approaching, what is my plan for the impending new year?

My ASX share portfolio in 2025

Well, this might sound a little boring, but I won't be changing too much. I like to stick to my investing plan regardless of what might change in the global economy or the stock market from year to year. As Warren Buffett teaches us, good investing practice is mostly a static art, not something that, like an iPhone, needs to be constantly adapting or updating.

Most of the principles that worked for Buffett back in the 1960s still work for him today. I'm no Buffett, but I do try and emulate this approach. It's my view that anticipating something and investing with that potential outcome in mind is a foolish endeavour (and not the good kind of Foolish).

So, I'll continue to focus on the highest-quality, wide-moat companies that are leaders in their respective fields and buy them at reasonable prices.

Saying all of that, I do confess that I've been making some small adjustments to my investing throughout 2024, which I anticipate to continue into 2025.

As I discussed last week, I view the current market as a bit frothy. Even though markets have dramatically come off the heat this week, Commonwealth Bank of Australia (ASX: CBA) and many other blue-chip ASX stocks are still at historically high levels, as are the exuberant US markets.

As such, I've been finding it difficult to make investments at prices that I think make sense in the current environment. But I'm happy to take advantage of high interest rates and stack more cash than usual. I could well continue to do so next year. For how long? Well, we'll find out in due course.