Is this the proper way to fuse a DC/DC Converter?
I am not a total expert on fuse selection, but I have learned a few things over the years, not all of which are mentioned in the other answers. It is definitely correct to say that fuses are there to prevent electrical fires and not to protect circuitry. They pretty much never act fast enough to save your silicon parts, and that is not their purpose.

Fuse sizing considerations:

1. Average DC load and de-rating for load 

If your average load is 7 amps, you want to leave a little head room to avoid the nuisance of having the fuse blow without any fault present. You could use something like 25% or look for a selection guide from the fuse vendor.

2. Ambient temperature and de-rating

If the temperature near the fuse is likely to be high, then you may need to de-rate for temperature. Fuses blow at lower currents when they are hot.

3. Inrush characteristics and de-rating for inrush

If there is a repetitive temporary surge of current in excess of the fuse rating (for example charging up a capacitor when power is connected or disconnected or turned on or off) then you need to allow for that (see reference below). If you fail to allow for this, you may find that your fuse blows after 10 or 20 connect/disconnect cycles.

For the three above issues, take a look at this reference. If it becomes unavailable over time, just search for "fuse selection guide" and look for a good fuse selection guide from a well-known fuse vendor.

http://www.schurter.com/content/download/194051/5552460/file/Guide_to_Fuse_Selection.pdf

4. Maximum interrupt capability (based on supply characteristics)

Fuses have a maximum interrupt capability. In other words, in some cases, if the fault current is too high, especially if it is a DC current, the fuse may be unable to interrupt the current (due to arc formation or some other reason). If your 24V supply is based on deep cycle batteries, you should consider this for F1. The best way to  handle this depends on many details, so I can't give you a specific recommendation here, but there needs to be at least one fuse or fusible link right near the battery with a very high interrupt rating. The interrupt rating should not be confused with the fuse operation rating. A 10A fuse could have an interrupt rating of 100 A, or 10,000 A or some other value. As a concrete example, you can look up ANL type fuses. There are other choices as well besides ANL, but that is one well-known type of fuse which could be used in series with a large deep-cycle battery.

One final note: you have to make sure that the cabling is thick enough to conduct the rated fuse current without catching on fire (or igniting something else). So if you use a 35A fuse for F1, that might be OK as long as the wire running from F1 to the converter can safely conduct 35 amps. This basic principle needs to be applied to the whole system. With F1 protecting the converter, F2 does not really need to have a high interrupt rating. For one thing, the DC-DC converter probably has a somewhat modest short circuit current. And for another thing, if a fault current is higher than F2's interrupt rating, you will almost certainly be drawing enough amps from the 24V supply to blow F1.

Hope that is enough to get you going.

McKenzie