I try and keep my buys to a few hundred dollars or more. UTXO management can get pricy with higher fees. My exchange of choice has a $200 minimum for on-chain so it works well.

I watch price TA a bit and buy the dips or bottom of price ranges. If I end up watching for a week or so and nothing is materializing I just smash buy since I know I'm playing around with small price changes usually (aka sideways chop) and it's a waste of my time to watch charts all day. (it's fun to snipe lower prices in small doses and usually helps cover most or all of the exchange spread).