Way to many straight lines and single plant types.
In general, Landscape designs should consist of the following (NOT talking trees here, just mainly smaller planting beds like you have)
Focal pt- your single plant that draws the eye
Accent plant- not needed but a plant or small group of plants that sets off the focal point
Filler plants- groupings of plants that move they eye throughout the landscape
Mass plants- groups of plants that form a mass, usually use these in the front with a ground cover or something that creates almost a blanket
Little secret- use the 2/3 rule for almost any measurement
-plant height should be 2/3 or possibly 1/3 from the plant behind it.
-plant 2/3 cool plants, 1/3 warm plants- warm plants (reds) draw the eye more, youll need more cool plants to offset it
-Many more times to use this, to lazy to list
Formal landscape-Lots of straight lines, hedges, many focal points, LOTS of maint, think super highend mansion
Informal- Almost all residentials are these, curvilinear lines, plently of plant cultivars, fewer focal points, much less maintenance, uses natural plant form
Create areas or outdoor living spaces by using bumps on corners of the house- Ever notice of some landscapes have bump-outs at the corners and some other place around these house? the reason for this is to create spaces and stop the eyes from wondering. These bumps usually have some sort of focal point to stop the eye from wondering
Plant the right plants- obviously the right hardyness for your zone but also think shade/sun, water availability, mulch or rock? (Rock will usually need hardier plants in my experiance) etc.
Use a good mix of ever greens, perennials and woodies- your looking for season long interest- Spring for mostly shrubs, summer and fall mostly perennials, winter for evergreens
I always try to sway the customer in using MULCH NOT rock- rock is a PITA to work with after being installed, ontop of being a much harsher area for plants the grow, if you use wood use plastic or weed barrier, if plastic use a pitch for to pop holes around the plant to let H20 enter
DONT use fabric with mulch- dont, just dont. Mulch turns into soil, after a few years your left with soil under fabric under soil. Mulch is natural fertilizer when it breaks down andwill help the soil composition
Use odd number plants up to 7, 7+ it doesnt matter, it creates a mass planting
I could go on but