Some idea

I like celerygirl idea of keeping the foundation empty and planting along the sidewalk.

Do you know your zone? Take a drive around and see if there are landscapes you like. Most people will share their experience. Local nurseries should also be able to help.

The only plants I would put near the foundation would be at either corner of the house. Make sure it is planted to allow about a foot between the edge of the plant and the house at maturity.

I would mulch around the tree and plant on the perimeter. I would continue the plants on one side or the walkways.

I would paint the deck a light gray and the large post white unless it is a special material.

(So funny that the fence has a cutout for the tree branch.)

You need to think of everything you have ever wanted in your yard, even if you can't afford to do it all right now. Also, how you usually use your yard. You did not say if you have or plan to have children.

Then draw out a plan on paper of how it would look. Very simple but it must be to scale. It is easy to do on grid paper. You can use symbols to indicate trees and shrubs and such. You do not need to be a good artist.

I do have a few thoughts about your front and back yards.

For the front yard I would keep it simple and plant a hedge on each side of the steps. I would place it equal to the beginning of the steps or perhaps a foot forward.

I would use evergreen plants. I cannot recommend plants as I do not know your area. It does not need to be a sheared hedge.

I would grow nothing behind the hedge. I would heavily mulch, maybe with straw.

I would also have a bed for either perennials or annuals in front of the hedge.

It would be nice if you could have a small tree like plant on the right side of the yard. I don't know if it is feasible as I don't know where the lot line is and I can see overhead wires. It could be something like a lilac trimmed into tree shape. I did not try to draw it. Some people like plants at the corner of their house. I don't think it is needed and would be careful because of the driveway but I show one anyway. You could have one on both sides if you like.

Your yard looks large and it would be quite expensive to buy enough plants if you fill it in this year. I don't expect you to do that but you need to plan what you want for the future.

You have a lovely stately looking home! I would add gardens to the front of your house and on the slope like celerygirl suggested. Not next to the house because I wouldn't want to cover your basement windows since they are part of the architecture of the front of your house. Maybe add a couple of BIG pots of flowers on either side of the bottom of your stairs. Your big backyard is a clean slate so you need a plan. Currently, your tiny outdoor living area is jammed right up next to your house. Consider adding something that will get you out into your yard, a destination. Perhaps a firepit in the middle of your yard? Or a pool? Even something simple like a wood bench under a tree. Whatever you decide, it will be a fairly high budget since you are starting with almost nothing. Work phases into your plan so you can spread that high budget over a few years. Good luck!!

If you live in a cold climate, a pool might reduce the value of your house. Every house with a pool I looked at, I calculated the cost of filling it in. Admittedly the yards were smaller, but still.

I'd start with some trees along your property line, although a big tree at about 2/3 of the way to the lot line would be nice, too. An Amelanchier will give you wonderful spring blooms and grow tall. I like Fruit trees, too. Although you can find advice saying prune, spray, do this, do that, I find that if you just plant it and forget it, you will generally get some harvest most years and a good harvest some years. Following the advice will probably get you a decent harvest almost all years.

Unless you want a hedge, I'd think you want to vary heights along the property line.

Love your house! You back yard needs a fire pit so you can use your yard in the Spring and Fall too. It could be simple on the grass, or pebble, or go all out with pavers.

For me it would begin with sloping cheekwalls and widening the walk. Would do groundcover on the yard slope and small "putting green" at top.

I love the idea of a fire pit in the backyard! They're easy to maintain and you can find all different types and sizes. I think you need to consider how you use the space in the back and go from there. Do you like having lots of people over? Do you want more privacy? Once you figure out your needs/wants, design around your dreams. What have you always wanted out of a backyard?

For the front I absolutely love Dig Doug's Designsidea. The planter delineates the lawn from the house and creates a sense of privacy. Colorful trees and plants warm up the front so it looks less austere. Since your house is a darker color I especially like more colorful plants up front.