In order to get your players to do things other than simply attacking and defending in conflict, it might be necessary to understand why this is what they are so focused on. I have played quite a few RPG systems as a player that have influenced my play style in Fate. The biggest influence has been D&D, which taught me that all I have to do in a fight is attack. In Fate, it took me some time to learn attacking was not my only option, or even always my best option.
In order to learn this fact about Fate I needed to learn the rules, take some time actually practicing said rules, and realize that attacking was not always the best option or the most fun option.
Say your Players PC's are in a fight, and they just attack every turn and eventually win/lose (something like "I shoot him, I shoot him again). now imagine that instead of that, you have them roll notice at the start of the fight, and one of them notices that the monster they are fighting is only focusing on one person at a time. Then one PC with high/decent Provoke (or deceive ,or equivalent distraction capable skill) rolls well enough, or even has to spend Fate points, to put the "Distracted" Aspect on this monster and hands the free invoke/s to the next PC in line who then rolls to attack. if there are multiple free invokes they can use more than one and even spend a Fate point to get +6 (plus 2 for each free invoke and plus 2 from Fate Point) or more on this attack. That is a more interesting style of play, and you just need to be able to show them that, I think.
In order to show your players that using create advantage can be fun, you may need to sit down with them and have a practice session (talk to them about this first, see if they are up for it, try to convince them). If they want to use the characters they have already made, and you want to use the same setting, that is fine. I recommend they make practice characters, and if they do you should advise them to put a decent amount of points on skills that are good for create advantage. skills like Athletics, Physique, Deceive, Provoke, and Stealth (Stealth isn't the best example though). If the monster you make for this practice battle has Armor 2 and your PC's have no weapon rating, this could also drive home the fact that simply attacking for this fight isn't the most efficient option (if your PC's have a weapon rating, make the Armor rating of the monster 2 higher). Now this is important, Have the Players decide their character's "stats" first ** then tailor your monster to have a decent (but not too high, maybe the same number or one point higher) defense against their attacking skill, **but abysmal defense against create advantage your PC's have some good provoke? give the monster 1 or 0 will (or whatever skill defends against provoke).
Make sure your players understand that the point of this exercise is to show them how create advantage can be useful to them. If they know their attacks do 2 shifts less damage than they rolled, but their create advantage rolls will be virtually undefended against, they will realize (or you will tell them) that a create advantage roll is mathematically stronger. If one PC rolls 6 on Fight, (as an example attack skill) and the monster rolls 4 to defend, your PC did a 2 stress hit that was negated by armor, and gets a boost. If your PC rolls 6 on provoke or deceive and the monster rolls 2 (because they exploited his weakness) to defend, they just created an advantage with style that they get 2 free invokes on, which they can pass to the next attacking PC to give a plus 4 bonus that can go up to plus 6 if they spend a Fate Point. this helps against the armor rating and still helps do extra damage.
lastly, as more or less a footnote, you can remind your PC's to try and do some reasonable Create advantage rolls before fights start as long as they have the time and know that the fight is coming,as well as when and where. for clarifications sake, you should allow them to make such create advantage rolls when it seems appropriate, and should not be allowing them to abusively make more than seems entirely reasonable.