As a White Mage, you can go down many roads for gear, such as: +MND gear, +MP gear, + MP Recovered While Healing gear, -Enmity gear, +Skill gear, defense gear and Melee gear. Many factors can influence what kind of gear is right for your White Mage:
Firstly, depending on your Race, you may want to take one kind of gear over the other. Such as a Tarutaru with an overabundance of MP would be more likely to take +MND gear over +MP; or an Elvaan with an overabundance of MND would be more likely to take +MP gear over the +MND.
Secondly, level. From levels 1-10 it is not always necessary to have the best gear since you are most likely to get by those levels rather quickly. Once you start partying though, you will want to really start considering what direction you want to take your gear in. I always wore +MND rings when I was lower levels. No matter what Race you are, the +MND helps your Curing, even if by only a 2-4 HP than if you werent wearing the rings, those few HP can save someone's life. While at higher levels, gear becomes more important and it is best to spend more time thinking and planning over what your gear should be.
Thirdly, Gil. A lot of the good WHM gear is expensive and it gets worse the higher up you go. Sometimes you will find that an armor piece that you want is out of your price range. You have two choices: You can either stop leveling for a while and try to make some Gil to get it, or you can substitute the item for something less expensive. It all depends on whether or not you think it is worth it. You can measure the Item's worth by considering how many levels you can use it for, whether it will come in handy while doing Capped BCNM or Missions, whether or not it can be stored and whether or not you can use said armor piece on another job that you might be leveling now or will be leveling at a later date.
Fourthly, Availability of help. As you will see, there are many good WHM Armor pieces that are Rare/Exclusive, in other words not sold on the Auction House. In order to get them you will have to kill some kind of Notorious Monster (NM)(spawned or forced-pop) and most of the time in order to do that you need to gather some people to help you do it and/or go through the trouble of getting the Time of Death(ToD) of the NM that drops the item or camp for hours at end with no clue when it will pop (if its a non-forced pop NM like many of them are at least). Now this can be a real pain, especially on some of the NMs that are 21-24 hour spawns. Hopefully you make friends early on in the game but if not you can always try shouting for a party to help you kill the NM or farm to "hire" someone to help you kill it. Again, depending on the item, you need to figure out for yourself if it is worth your time to obtain it or continue on. I find that most of them are, but again it depends on your opinion of what is worth it.
Lastly, Your personal preference. In other words, how you feel your White Mage should be, while still doing the job required of a White Mage. I am a White Mage who takes pride in doing my job to the fullest of my abilities. I personally lean towards as much +MND, +MP Recovered While Healing gear (also known as hMP gear) AND +MP gear as I can get. I prefer that over -Enmity and Melee gear. Since I am not a WHM who likes to be out there attempting to melee or take hate in my party, I shy away from that kind of gear unless it brings me a good MND or MP bonus compared to something else at its level. I personally do not believe it is a WHM's place to be putting their party members in danger by not having the ease to do their job to their fullest potential that standing apart from group gives them. The whole point of having a WHM in your party is have someone MORE THAN just a healer in the party. If they wanted a Sub-Par Healer they could invite a SMN willing to be Main Heal, for some reason there are many SMN out there more than willing to do it. Also RDM can be very good healers if they have to be. But none of the other jobs that can heal are as good as a White Mage due to the WHM only spells. A WHM should never think they are irreplaceable though, because if you aren't doing your job well, you CAN BE REPLACED!! That is just my opinion and experience after playing for a few years now as a WHM. While some newer people seem to think that is outdated and close-minded, I still follow that since it has led me this far with a good reputation and many friends on my server. Now, the reason I am including Melee Gear on here is to show you what is out there for a WHM who likes to Solo and do Damage in non-experience point party settings, such as Ballista, Skill-Up Partys, Duo-ing, Farming, etc. I really do not advocate meleeing in an Experience Point party, but if you chose to do it, that is your own choice and here is still gear that you can use for it.
Side Note: As I did in Weapons, I am using BOLD for all the gear that I used as a WHM for one reason or another.