Since I started from a blank (literally) due to building our house in 2005, I can tell you how I did it. I did space for growth, so I don't yet have those masses of bountiful blooms as you'll see in other photos on the forum.

We mulched well for the last two years using organic soil amendments and triple ground hardwood. (Pine straw is actually outlawed during drought around here as it considered a great fire hazard).

First, we installed hardscape (fencing, water features, main path).

Then, we installed a few trees of good size already (7-8 ft) and 3-5 gallon shrubs to give us some bones.

I added some 1 gallon size "anchor" perennials for edging such as lavender, nepeta and dianthus.

Next, laid drip irrigation (no oversprays here)

Mulched.

Since it was fall, I planted daffodils/jonquils/bluebells/Dutch iris bulbs.

The following spring/summer, I planted more perennials and annuals (snapdragons are my favs).

Then, we decided to expand the garden beyond our original fence to make an outer garden (deer and drought tolerant, but attractive to birds and butterflies), so we did the same thing again:

hardscape (patio and paths)
big stuff (5-6 ft trees and 3-5 gallon shrubs)
drip irrigation
bulbs
perennials (1 gallon size and a few plug sizes)
mulched

If you go back through my blog, you'll see how it started sparse.

Hope this helps.
Cameron

Here is a link that might be useful: look at photos from the beginning

I leave less space than recommended, but I don't smush certain things too closely. Give them at least a few inches.

GGG

I give perennials space to develop and fill in with annuals until the plant reaches full size. I may plant 3 at a time and reposition if/when it becomes necessary.

Libby

Ditto what Libby wrote.

Have fun making your new beds!

Patti

I prefer to sparsely plant with only one or at most two of the same plant per area. The idea is that they will naturally forms drifts - through seeding and or roots.

I feel it looks more natural then close setting of the same plants in groups of 3's and 5's.

Cheaper too.

When I started, I planted giving them what I thought was enough spacing, but I have had to move things because they got much bigger than the labels stated.
The last bed we did, I actually measured out the fullest in diameter that they are supposed to get, so we'll see. I guess I'll find out over the next few years.
I don't mind if they are closer, but if they start looking like it's hurting them, than I'll move them.
This year, I have to divide salvia,lambs ear,sedum,and bluebell.

This is a popular question in the cottage. I think you'll find everyone has a slightly different opinion on this. Some squeeze as many plants in the space as possible, then move later. Others plan for growth. And still others crowd some and leave room for others.

I would advise you to look carefully at what you'll be planting. Give those shrubs room to expand because you won't want to disturb their roots. Also, those perennials which resent being moved- make sure they'll have enough room to bush out. I say, everything else is fair game. Squeeze 'em in!

Have fun!

Tracy