Metallicat here, and first I’m just going to say that there is no big secret to unlocking items for kits, vehicles, and weapons in Battlefield 4. There are other games where your choice of actions can boost your rewards considerably, but for the most part, you can’t control those in Battlefield.
The Basics Of Advancement
The biggest factor besides your skill in active play are the XP boosts. You will get many of these in the course of the game, and will hit a point where using one every time you play will let you gain replacements before they expire. But in your early career, you may not have quite so many to use, so choosing when to use them requires careful planning. Double XP events are cumulative with the XP boosts, so saving the higher 100% and 200% boosts for those can be good — they give 4x and 6x XP respectively then.
On the other hand, if you are playing to explore the map and try out things, and won’t earn many points during that game, the XP boosts are wasted. Once you are above rank 10 you will start to get enough new Battlepacks to get more boosts. Rank 50 is the golden rank, literally — you get Gold Battlepacks at every rank starting here. With five items each, the odds are good of getting at least one more boost, but I’ve had some which were all boosts.
It isn’t your overall rank, though, which is critical for game play. It is your advancement in kits and vehicles, and to a lesser degree weapon classes and attachment unlocks. Because your earned XP count for both the kit or vehicle you are operating and your overall rank, you are going to complete the unlocks for your favorite vehicles and kits relatively early in your career. You can complete all kits as early as rank 25, but are likely to spend time in vehicles and may take until rank 30 or more to do that. Vehicles are dependent on both how much time you get to use them, and how skilled you are — especially, not dying and thus losing your ride. Even so, you should expect to see all of your favorite kits and vehicles fully unlocked by rank 50.
http://battlefield.wikia.com/wiki/Battlefield_4_online_ranks
Weapon classes require you to use the weapon and gain points from kills, which do receive XP boosts. Weapon attachments are unlocked only by kills, and don’t benefit from the boosts. For both of these, you only need to kill enemies, which is after all what weapons are for. The Grenade unlocks are similar, but because you are limited in how many grenades you can quickly get (one M67 Frag per life at the start), until you have them all unlocked you should use them whenever you get an opportunity.
Playing For Score
The good news is that if you are playing the game well, this will come with no special effort. Just remember the Newbie advice and do these key things in every game:
Join and play with your squad.
Do your job – use your kit equipment to support your team. Especially medical and ammunition supply.
Spot the enemy.
Follow orders, give orders if you are squad leader.
Play the objectives. Attack or defend flags or M-COMs.
If you are the last one alive in your squad, try to stay alive. But remember that you earn XP by attacking and killing, while deaths are a mere time out with no XP penalty.
To maximize the rate at which you earn points, get into the heat of battle. Try to stick around the areas where the fighting is fiercest. Fortunately, the game objectives tend to be this, giving you bonus points.
http://www.bf4blog.com/battlefield-4-fast-xp-10-tips-rank-fast/
Games with more players and areas with concentrated action will give you more opportunities to score points quickly. But almost all maps and game modes offer an aggressive player the opportunity to find intense action and kill the enemy.
Wait, There Is A Big Secret
Medals and Service Stars give a huge amount of bonus XP when you earn them. You get medals for every 50 Ribbons you earn, and you will earn many throughout your career. You get a Service Star for every 100 kills with a weapon. You get nice big ones for each kit and vehicle, every time you earn the last unlock’s XP for it. You also get them for game modes. You can see these on your Stats and Awards pages.
The “secret” part is that XP boosts apply to the bonus XP from Medals and Service Stars. So it is possible to get close to earning one of these, and then work to get another close, and so forth, then use a high XP boost and get a huge multiplied bonus score.
I have mixed feelings about this — you are earning a big bonus on something which you worked on before you activated the boost, and this encourages a degree of micromanagement which can distract you from simply playing the game. But if your goal is to get all the kit and vehicle unlocks, this method doesn’t offer any advantage since you haven’t yet earned the first Service Star — and when you get it, you have achieved your goal.
It is worth keeping in mind if there is a Double XP event or you are planning to use one of the rare 200% boosts and want to get the most value out of it. I love earning higher ranks, but they don’t give any game play advantage.
Play Well, Have Fun, And Your Unlocks Will Come
Concentrate on playing the game as well as you can, have fun, and before you know it, you’ll be unlocking new, useful things left and right. You won’t get everything overnight, but you should get the things you want most for the kits and vehicles you use most fast enough that it won’t feel like a grind.
