You pretty much have a blank slate. However, if you remove the tree it will definitely affect the light in the yard. With the tree in place it is shady from the picture at any rate. I don't know what time of day this is.
Decide if you want the tree removed, you may have to wait on the yard until after that.
My suggestions assuming this house will have at least 6 hours of sun when the tree is cut down.
1. Decide on the sytle you want the garden to be and the amount of time you want to spend on maintenance.
2. Paint the house. The door should be painted a contrasting color that pops. Right now it looks distant and blends in with the wall. Add a railing to the porch for privacy and you can put planters on the rail
3. If you store your garbage cans out front. Build a surround for it. My HOA would cite me if my cans are visible. It does not have to be tall. My cans are out front, just disguised behind a low wall and plantings. It can be seen from the driveway side but not directly from the street.
4. For future maintenance on the house it is best not to plant 18 -30 inches from the foundation. Clean up around the foundation, put down a woven weed barrier (good for 15-20 years) and put down a mulch. You can use this path to do maintenance on the house, it keeps the roots of the plants furter away from the foundation and helps when you have to maintain the plants. It also gets things out from under the eaves.
5. Consider replacing the side walk with something more decorative down the line or painting the sidewalk. The popular colors here are a burn't red and green. You can add a mold inhibitor to the paint (if they still sell it) to inhibit the black algae and mold from growing. Otherwise, there is always the power washer. I myself do not like a straight sidewalk but it depends on how you use it. If this is not your main service entrance, but more of the 'curb' entrance. I would use put in a more meandering or curvier path to add interest. I would use stepping stones from your service entrance to the door you usually use. Around here the front door is not the one the household uses unless the driveway is closest to it. Most often the household entrance is the kitchen or garage door closest to the car. You might as well put in a secondary main pathway that is at least wide enough for two people otherwise you end up with a compacted trail where you end up walking all the time anyway.
6 If you want to keep the sidewalk you can make it larger by adding to the sides either more concrete or pavers as and edge to widen it and add contrast. Those can be painted too a different color but muted. You want to see the house not the sidewalk. The stairs at the house is wider than the sidwalk make that entrance wider too. put a semicircle of concrete the width of the stairs at the base of the stairs It widens the end of the side walk and makey you feel like you are in a bigger space it also transitions form the stairs to the narower sidewalk.
7 beds surrounding the sidewalk should be colorful, wide and curvy. Not a narrow row of tight plantings. It makes the sidewalk look even more narrow. Colors depends on the colors you choose for the house. If the house is painted more in earth tones then select 2 or 3 colors and repeat. Too much color looks dissociated but works if you like a cottage style. If you want a more orderly, formal appearance then you have to limit your colors. Plant in drifts or groups of t three or more and carry a theme all the way through. By carrying a theme I mean everything should be complementary. Your house style can work with cottage and more formal styles but it is definitely contemporary and not Asian. A moon gate would not fit the style, but an arched arbor would. If you had a hacienda style house, a Japanese garden looks strange. What you plant there can be a mix of annuals, perennials and bulbs. Some variation in texture and color in the leaves add interest but you want to repeat the combination throughout and not put annuals one place, spikey plants one place, and sub shrubs in another. A drift is one thing it should look layered not laid out in succession.
7. Planters on the side of the stairs to frame the entrance. Add some yard lights if you use this path way at night.
8. To soften the corner of the house a shrub would work there. You want a tall element to anchor the plantings and soften the sharp corner. Try to avoid planting in a row but stagger the plantings of permanent shrubs and perennials and leave room between for annual colors to fill in. What you choose depends on your location, the plants that do well in your area, what you like and how much maintenance they would require.
Since you are still working on the house. I suggest you come up with a master plan. Prioritize what needs to get done first, and work out a time schedule that fits your ability and budget. You don't want to put something in and then have to rip it out later to put in something else. Take your time choosing your colors and your plants. It is a good idea to do some research. Take a look around the neighborhood and see what grows well and how big they get. Borrow some ideas from the neighbors that you like. Have a rough idea of what you want but don't lock in your choices. Like a tall shrub to soften the corner. Decide how tall, how wide, deciduous, evergreen, flowering. Look at some choice and research how big they get and the amount of maintenance they require before you purchase them. Get the biggest plants you can of foundation shrubs. Small foundation plants take a long time to look good. The seasonal and faster growing plants can be smaller.
1. Cut down tree and observe change in light patterns throughout the year. This will tell you how much light you will be getting in the different seasons
2. Add railing to porch and planters. Paint the house.
3. Build garbage can surround
1 Decide what to do with side walk. widen, paint or change material.
Entrance arbor optional
2. Put in foundation plants you have chose after researching and place them in position based on your master plan.
3. You can work the yard in sections or do it all at once. Prep the yard, weed, remove old grass, amend with compost and fertilizer. Put in sprinkler system if you are going to do that. This part can be hired out to a landscaper. They have the equipment and can get it done in a short time. If you have nasty weeds you may want to sterilize the yard in year one. It usually requires a professional since the chemicals are not available for home use. Nothing will grow for one year but you end up with a blank slate.
Define planting beds. Put in edging if you want to keep some lawn. Curves are easier to mow around than sharp corners. Lay bricks around edging flat on the ground. this is for the mower wheels and it is easier to keep the lawn separated from the border beds.
4. Put in plants in season according to your master plan. Measure the beds and graph it out on paper. Space perennial plants according to their mature size. Plant in groups and drifts, and repeat. You can fill in with annuals. You don't want to buy plants you don't need and will have to take out later because it is too crowded. Initially, it will look sparse until the landscape matures. Mulch to control weeds and retain moisture.
5 You will have time to tweak the plan, it is o.k. to change things, some plants may not work out as you thought, or you might find something else you like instead.
This is not going to be a quick fix.
Happy gardening in Hawaii. Gardens are where people grow.