Honestly, I'm not good at analyzing the market or using the tools provided by the market to analyze candles based on price and volume movements. My day trading only relies on depth and EMAs 15, 20, 30, 50, 100, 200. So I'm not really thinking about which one to buy, BTC or ALTs. But this is what I do, always buy Bitcoin every 2 weeks regularly in small amounts, $10 - max $100, then I sell some when the price really goes up high, since 2016 I have never traded BTC/FIAT, for Bitcoin, I just swapped to a Fiat, then I cashed out.
This is also what I recommend, use some to buy bitcoins, and part others for alts, spend wisely and sell them when the price really hits your target price.