Some observations, considerations, and suggestions -
Please bear in mind that most of this is based on the assumption that your home is primarily wood framing with drywall or plaster.
Ethernet is a good thing to have, even if you're not going to take full advantage of it now. You may decide to sell later, and a wired home can be of added value to a savvy home buyer.
While the need for wall jacks has gone down quite a bit since the advent of WiFi, cable TV is still going strong, and there are many folks out there that prefer the stability and performance of a wired ethernet connections.
However, most folks don't consider the ramifications of wall-jack placement.
Consider this - you've just purchased a house. It is not yet furnished.
You walk into your living room or den with your TV in hand.
What is the first thing you do? "Look for the wall jack". . .
Hmm. Wall jack is over there, so the TV has to go there, which means the seating area goes over here. . .
For many folks, this is the end of the road, as they don't always want to deal with having new jacks put into place.
Something as simple as the placement of a wall jack has forced their hand as to how their room is laid out.
This is particularly true when a room is "divided" into sections, via patio doors, closets, and other walkways/doorways.
So, take a peek at your living spaces, and see where having ethernet, coax, etc., makes sense.
If you have a room that is divided in such a way that you'd need to run a cable across or around a doorway, walkway, etc., then plan to have a jack on each side of the room.
I find that having a jacks in the corner more convenient that having one in the middle of a wall, as it can then more readily service either wall.
Of course, you may not be able to conveniently access each area for jack placement, so you may have to adjust your placement accordingly.
Pulling wires through exterior walls on existing structures is usually the most difficult, particularly on 2-story homes.
Therefore, typically recommend utilizing interior walls as much as possible.
If your attic is completely unfinished, your job just became a bit easier, as it is a snap to distribute cables to the 2nd story from above. This is mostly due to being able to directly access the top plates of the interior walls below. Simply drill a hole straight down through the top plate, and drop your wires down into the cavity below.
Cables for the first floor can be routed upwards from the cellar, also assuming that the cellar/basement isn't finished with ceilings, etc.
Drilling up from the basement can be a bit challenging, as it isn't always obvious where the wall cavities are.
Sometimes, you can follow electrical wiring in the basement to determine where the walls are from below, but that doesn't work in every situation.
A safer method is to first decide on where you want your wall jacks, and then scope out the general area in the basement below, to make sure there aren't any potential obstacles in the way. If everything is clear, then cut out your opening for your wall-jack upstairs. You can then use that opening to insert one of those long, flexible drill bits into the wall cavity, and drill down into the cellar. If you're not familiar, see the link here:
https://www.amazon.com/dp/B00DNEE3QM
Although less recommended, if you are replacing your baseboards, you could potentially notch out a small channel in the drywall, let's say 10mm wide by 50mm tall, right at ground level. Then drill a hole at the base of the channel, into the cellar. You should be able to notch out enough drywall, (and potentially a small amount of the stud behind it) that you can route a cable into the wall cavity, and have most of the notched out section concealed by the baseboard when you replace it. Just be careful to not put a nail through the cable when re-installing the baseboard.
I have seen some creative folks conceal cable along a wall by using the small gap between the bottom of the baseboard and the floor. The location they were trying to reach was under a 10-foot wide section of window in a concrete-slab home, and thus virtually impossible to reach without using some sort of surface-mount solution.
The easiest solution downstairs would be to simply drill down right next to the baseboard, and install surface-mount jack(s) to the baseboard, directly above the hole.
Obviously this is may not be an aesthetically pleasing option.
While not required, and depending on the size of your home, you may want to look into the feasibility of running cable to some centrally located areas above the ceiling, for wireless access points.
Perhaps one in the hallway upstairs, equidistant from the center of the two bedrooms. The attic should make installation fairly easy, unless of course it is a finished attic space.
Downstairs might be a bit tricky for a ceiling mount, since you have the floor above to contend with, so there, you might want to consider a discretely placed centrally located wall-mount access point instead. If you are planning a wall-jack nearby, you can always install an access point on the same wall directly above the wall-jack, and both cables can share the same hole down into the cellar.
You'll have to decide where you want all of your cables to junction, which will in turn affect other decisions. . .
The biggest potential challenge will be getting the cables from the attic down to your junction point.
If you already know how to accomplish that, great. If not, here are some potential solutions, with caveats. . .
Conduit on the outside of the house. Efficient, but not aesthetic. Requires you to transition to outdoor-rated CMX cable for the run outside. (Regular cable, even when in conduit, will deteriorate in relatively short-order as it readily absorbs moisture, causing the cable to crack & split.)
Sometimes you can utilize the same wall cavity as plumbing vent pipes. Those will usually vent to the roof via the attic space, creating a chase-way of sorts that you can use. However, fishing the cables through could be problematic, and you may find that you have to cut out drywall in a few spots at floor/ceiling level, in order to route the cables through.
If you do find some sort of easily accessible chase-way, you might want to consider installing a section of plastic conduit, flexible piping, smurf tube, etc., and then pull your wires through that. . .
If you're fortunate enough to have closets or utility areas directly above/below one-another on the first and second floors, you could cheat a little, by carefully drilling down (with a long drill bit) in the the corner of each closet, into the closet space below, and route your cables that way, using something like Cord-Mate III to conceal the cables. I do say "carefully", because you never know if plumbing or electrical will be passing by the spaces in between floors.
Hopefully, this will be enough to go on. Reply back if you have any further questions/comments/etc.