Does buying and selling ETFs work similar to stock, ie buy low sell high? What are the indicators to consider when choosing ETF? Expense ratio? Any indication when to exit or when it fails?

Thanks for the good info everyone! Just wanted to value add to other readers. A common interest people have is to advocate and go for Irish Domiciled ETFs, as Chris mentioned, to reduce tax. And that is fantastic!!

However, do remember the dividends on many ETFs such as ARK funds, S&P500 ETFs or QQQ do not actually have that high dividend yield. The 15% tax relief switching from US to Irish ETFs may save less than you think. Of course, saving something is better than nothing right?

However, do remember to compare the spread between bid/ask price (sell/buy)

The % difference may shock you that you may actually be saving much more on ETFs with better spreads than focusing on reduce tax. Of course, if you can find the best of both worlds, that will be fantastic! So, do compare ETFs form both countries and calculate what's best, it all depends on what funds or indexes you are trying to track as well.

Happy investing/trading everyone!

Yes works the same way, buy low sell high. THe only difference is the risk is more spread out since an etf have many stocks within. Some things to look at are expense ratio, liquidity trading volume etc. 30% tax is not significant cause your purpose is capital gain.