Yesterday I finally got my Blacksmithing to 440 and unlocked the nifty Titansteel goodies. I haven't actually made one yet since I need to collect a bit of Titansteel first. Since none of my toons is over 74 yet, I'm not actually in a rush to make any of the items either :)
The leveling process to 440 is not terribly complicated, you start out with green goodies that you'll probably make and sell at a loss. Cobalt prices are actually higher than Saronite right now, so it would be difficult to get a fair price for a cobalt item. If you're willing to go off the beaten path a bit, you can make better money by doing so. For example, at 390 you'll learn a number of recipes including the Spiked Cobalt Gauntlets. Now most folks who are in a hurry will make the gauntlets because they have the lowest ore requirement. On the other hand, if you are willing to sacrifice a bit more materials, you might be able to make a better return on your investment.
I actually started making blue items as soon as I trained them, including the Tempered Saronite armor and some of the Saronite weapons. Because there are less of these items on the market, I was able to mostly charge a fair price that covered the market cost of my ingredients and in some cases make a reasonable profit. You'll want to keep an eye on your auction house and try to sell items that are in low supply if you can. Since there is some variation in that, sometimes you still end up with something that sold well the first day but isn't selling today. This is where it's good if you have a sense of what items are appealing to various classes, so use that info to your advantage if you have it! Don't make 10 caster maces unless you know it's the best mace available at that level and the price you want to charge is a reasonable cost for it.
If you decide you're interested in going the "good stuff" route, I would suggest you focus on melee friendly gear and avoid the pally-specific items (sorry Pallies!). This is because there are more classes that can use tanking or DPS items than will buy plate with spellpower. For some odd reason, I see more Pally gear on the auctions than tank/DPS gear. This baffles me since we have only one class that can use spellpower and three classes that can use melee or tank gear. I assume it has more to do with the fact that the Pally gear is slightly cheaper to make, but I'd rather cough up a pricier crystal than sell my items at a loss, maybe I'm just weird.
Anyway, if you're mining your own ore and have eternals to use, I encourage you to use them in crafting useful gear for plate wearers. For now this appears to be a workable strategy for making money from Blacksmithing. I did this from 390 to 425 and so far the only items I can't seem to rid myself of are the green stuff I made to get cheap skill points. I still have 4 pairs of Spiked Cobalt Boots in my bank :(
Last night was my big final push from 420 to 440, so I planned carefully and gathered my materials. I started out making Eternal Belt Buckles, which I was a bit nervous about because it uses a lot of eternals, but it worked well for me. I was able to sell all of these for a good profit on the auction, two of them the same day I made them! You can check your auction prices to see if your economy is similar, but I'm hopeful that this item will turn out to be one of our ongoing consumables. The only problem for a non-miner is the Eternal Water, which I just bought from the auction (even though I have a fisher-person, be quiet :P).
Once I got to 420 I switched to Titanium item enhancements. While some folks may prefer making blue armor, I actually had a stack of titanium from mining so I chose to go with that. The price difference on my server between a stack of Saronite ore for one piece of armor and one Titanium Bar for an enhancement is pretty darn close anyways. First I checked my auction house to see what the going rates were, since the mats were the same for both enhancements. The weapon chain was selling for a better price, so I made those. If the shield spike is better on your server, make that instead. Personally I suspect the weapon chain will usually win because it's useful to more classes than the shield spike. At 430 you'll also be able to make Titanium Rods, so again check prices and see if it's going for a good price. From 425-430 you can either make Titanium Rods or continue making the various armor pieces that are still orange to you.
At 435 all of the recipes turned yellow, so you're on Elune's good graces for the last five points. I made Daunting Legplates and Savage Saronite Skullshields (both learned at 425) and I actually got a point for each one of them. You may not be quite that lucky, but it looks like the skill-up ratio is pretty high despite the difficulty rating of the recipes.
I certainly don't want to encourage anyone to go this route, since you'll just be stuck trying to offload the exact same items that every other Blacksmith wants to sell. But for those who just want to get there quickly, this is what I believe is the cheapest route based on what I'm seeing on my server:
375: Cobalt Gauntlets
380: Spiked Cobalt Boots
385: Sure-fire Shuriken | Spiked Cobalt Shoulders | Spiked Cobalt Chestpiece
390: Spiked Cobalt Gauntlets
395: Spiked Cobalt Belt | Spiked Cobalt Legplates
400: Horned Cobalt Helm | Spiked Cobalt Bracers
405: Brilliant Saronite Boots | Brilliant Saronite Pauldrons (consider using crystals for other items!)
410: Tempered Saronite Bracers
415: Tempered Saronite Gauntlets
420: Titanium Shield Spike | Titanium Weapon Chain | Daunting Handguards
425: same as above
430: Titanium Skeleton Key | Daunting Legplates | Savage Saronite Hauberk
430: same as above
Now, I'm aware that there are a few BoP recipes that drop in various zones which have a pretty low materials requirement (4x Cobalt bars). You'd have to be a bit higher level to farm them, so I hesitate to recommend it because of that. If you have the ability to kill 72+ critters, the easiest one to get appears to be the Reinforced Cobalt Shoulders in Dragonblight. I really can't say how well these finished items might sell, since they have Resilience, which is more of a PVP stat. Still, if you aren't skilling up on a lower level alt and you want the cheapest possible option, these Reinforced items look like a viable alternative to trainer recipes.
Good Luck and feel free to share any other tips you might have in the comments!