The simplest thing you can do is chase returns. Maybe you do that by looking at assets that have yielded large returns over the past N days. If you do so using total returns (i.e. price appreciation plus dividends, coupons, or whatever) that will bias you towards high yield bonds and high-risk equities. History says that’s honestly not a bad strategy.
If you decide you want to be less prone to buying high-yield assets that usually pay out but that could crumble at a moment’s notice, the next-simplest thing you can do is ask whether an asset has produced a good return relative to its long-term history. There are all sorts of reasons this could happen: maybe it’s a stock in a sector that recently became popular. Or maybe interest rates are falling and it’s a long duration bond.
In any case, it’s not obviously a bad idea to buy assets with recent good performance. “Hop on the bandwagon” works ok as an investment thesis IMO.
The key is that you operate in as many markets as possible and let diversification do the hard work for you. If you eke out a small edge that works across markets, on average you’ll do ok.
That’s my 2c on the systematic technical trading mentality. You don’t need to swallow it wholesale, but I don’t it’s fair to characterise texhnicL traders as a bunch of swivel-eyed loons either.