If your goal is for a positive K/D, I'd recommend trying to get at minimum 2 kills per sortie, this will ensure that even in you die a lot, you still go positive. Secondly, from a combat point of view, if you are going to be flying a brew, I recommend you get a lot of alt if you are flying to an enemy base, like 15k, and make sure you get some alt back after you dive on your first enemy. Its all about patience in getting your E back, not getting caugh up slow after you dive in. You will get jumped on very quickly if you go in under 5k without going atleast 350.
I'd recon to learn the strategy of attack vs defense planes. Planes like the Ki84, spit, Brew, La7, Yak ect, are great for defending a base. They turn well for counter punch and can gain alt and acceleration quickly to pounce on low BnZer who are diving in and getting slow. They are generally better for fights on the deck. Attack planes, like most of your American planes, Typhie/Temps, 109s (can be a good defense too), 190s ect are great for getting alt and attacking planes at an enemy base. They can dive well, escape from trouble easier after a dive, are better for attacking bombers, and generally have more ammo. They aren't very great at turn and burn and are sluggish on the deck which can make it an easy target to pick if you have alt over them.
If you stick to a rule of thumb on the advantages of attack vs defense planes, you will generally find more success with your K/D. If you only stick to one plane for both, than you will need to find situations for using those planes, like rolling off a CV with defense planes to attack planes at a base, or rolling from a back field in an attack plane to go defend your base that has enemies coming in if you don't want to use a defense counter punch plane.
Last tour I crushed it with the P47N getting a 22 K/D with 68 kills and also a 16 K/D in the F4u1d, so I do know a little of what I talk about. I normally do just what I mentioned above though know how to counter punch in those attack planes which normally throws players off because they dont expect me to get flaps out and turn. You do have to make sure you dont get picked from the guys behind them. So you may have to drag a player out for a bit to get them in a 1v1 situation if you can. Just a lucky month for sure, but i do like to keep it going when I have a good run. One of my other favorite planes is the Ki84, and I've been trying to get 2500 kills in that for the Jap achievement but it's taking forever! I've been really enjoying the P47 lately so might stick with that, or fly a P38 a few times. Will see how it goes.