Get a pair of standard 6.5" speakers. Pretty much anything you buy will sound good in here, because face it, you're driving a Honda, and even with the Advanced 6 Speaker System none of the speakers bundled with the car are going to be of any quality whatsoever. Run to your local super-cheap car-audio warehouse and pick up a pair of 6.5"s for less than $80.00. Make sure that they're rated in between 30-150 watts. They should also be 3-way. 3-way is more important that high wattage numbers. A two-way system has one speaker for bass, and one for mids and highs. A three-way system has one woofer, one speaker for the mids, and a third, the tweeter. Instead of dividing the entire audio frequency into two parts, a 3-way divides it into 3. Less work for each speaker. $5-10 more, and a whole lot better audio.
First, you want to pop off your speaker covers. They're the plastic bits with holes in 'em towards the front of your door. There are typically two ways to go at this. First, remove your entire door panel. This is inadvisable because you have to take off all sorts of other things, such as handles, and it can actually break your weather sealing. Second, just pull that cheap little plastic bit off. In theory it's a removable part, but it rarely actually works. Expect the plastic ties to rip off, and expect them to glue the screen back on later.
Now you can see your speaker. Wave at it. Look at it tenderly, because this is the last time you'll see it functional. Take out a Phillips head screwdriver (medium sized) and start unscrewing the speaker. Take care to unscrew the speaker and not the housing by going after the screws closest to the steel ring. There are three, and one is kinda hiding at one o'clock (if you imagine an analog time-teller superimposed on your speaker).
Once the speaker is completely unscrewed, gently, gently pull it out until you can see a big gnarly plastic thing on the back. Grab a pair of wire cutters, and snip the two wires coming out of the back of the plastic thing as close to the speaker as you can. You will need as much wire as possible later on in the process, so cut as close to the speaker as you can manage! You don't need the plastic thing on the back. Throw it out, leave it attached to the speaker itself, recycle it, or do whatever.
Strip about an inch of insulation off the wires that are now poking out of the door, all lonely-like. This will be difficult. Persevere. Get a wire stripper if you don't already have one.
Your speakers should come with two pairs of wires, matched in length. This is the tricky part that requires steady hands and clear eyes. One wire in your door and one wire (of either pair in your speaker box) has a black stripe on it. Keeping in mind the mantra of "red to red, black to black", the wires with the black stripes on them are the ones that go together. Bend the end of the wire in the door into a fishhook, bend the wire from the box into a fish hook (the manufacturers usually pre-strip these for you), hook them together, and twist until they're firm. Solder them with a soldering iron. This is far more intimidating than it is difficult. Just do it and before you know it, it'll be done. Try not to put too much on, you'll short circuit your shiny new speaker, and possibly your head unit, and because it's a car, you might blow everything so don't. Done soldering? Wrap the whole shebang in electrical tape and repeat the process with the wires that don't have a black strip on them.
On the other end of these wires that came in the box there are odd little metal thingies. One's small, and the other's large. Look on the back of your new speaker. There are two prongs, unsurprisingly, large and small. They're currently on a plane, with the same orientation as the imaginary plane formed by the ring of the speaker. large tab into large slot (I'm talking about the speaker and the bracket on the end of the wire respectively), small tab into small slot. Bend the tab/slot combos so that the tabs are now pointing towards you (as the speaker faces away). This is so that the speaker fits in the door properly. And that's it. I told you you wouldn't need the plastic conglomeration on the back of the stock speakers.
Put the speaker in the hole. Screw it in. Tidy up your wires. If you've bought a decent speaker system (which if you followed my instructions you should have) there will be a bunch of holes around the outside. Your Honda accommodates most speakers, your only problem is lining the holes in the speaker up with the holes in the plastic mount the old speakers were mounted in. The speakers you bought should come with screws. If they didn't, use the screws from your old speakers. Like I said, screw it in.
Glue the speaker covers back on, preferably with some sort of plastic adhesive. Repeat on the other side.
See, isn't that better? Now do the 6"x9" set in the back.
Based on personal experience! Dispose of all electronic waste responsibly! A guide aimed at getting you on the road with noticeably better audio, not a guide aimed at teaching you what everything is or does or means. <>This is not for audiophiles. <>Fast, Cheap, Good. Choose two. <>Not responsible for mistakes you make. Not responsible for damages to anything as a result of reading these directions either directly or indirectly. I'm just covering my ass here.