I've gardened with daylilies for over 20 years, and the biggest mistake ( one that I made repeatedly until recent years!) was planting them too close together initially. I've also learned that it is important to supplement your soil if you have poor soil BEFORE you start. Even if they look scant at first, MAKE yourself plant any daylilies that aren't registered as miniatures on 2' centers at the very least. I'm going to 3' centers now with large clumps. minis can go a bit closer together, maybe 18" centers. Fill in with annuals the first year if your beds look too bare but they will grow in to fill the space quickly. On the beds that have walking paths where you can walk on all sides of the bed, I plant by height with 3 rows, the tallest row in the middle. On beds that can be viewed from the front only, I also plant by height with the tallest in the back. Companion perennials are important for longer season color. In this climate, I use clematis at the back or on obelisks, various types of rudbeckias, echinaceas, Agastache, salvias, kalimeris is good here with a long bloom season. Oriental lilies (need plenty of room) spring bulbs but am now moving them to the rear of beds because they increase so quickly and can overpower in a few years. Some heucheras do well here in full sun, but probably would be risky in your climate. Some people like to group by color and I've seen nice white beds , blue and orange beds or others that are opposites on the color chart, "hot" beds of reds, yellows and oranges, etc. I prefer the diversity of color and forms all mixed together . If you plant perennials to give blue, white, chartreuse as well as columnar and textural interest, it adds a lot to your garden.