In general, the best way is to 1) learn the rules for pattern id, then 2) study charts of just price on a non-trading day. Learn the targets based on pattern dimension (e.g. Peak of Head to neckline projected from neckline for H&S) and see if they appear valid or could stand improvement. Try to identify 20 or more of Double Top/Bottom, Head & Shoulders, and Asc Des Sym Trianngles. Flag Pattern is good. Get really fancy and track the performance of each pattern or even their dimensions. Essentially - spend time with charts once you know what patterns you're looking for.
Reading books, forums can help, especially at first. Best Way ultimately is practice