I would echo what Ian said, the Anaconda is probably a bad choice to get into combat, more so if it isn't engineered. It would help if you could mirror your build in EDSY so we can take a look at it. But unless it has G5 drives, NPCs are probably flying circles around you. A few other random points in no particular order:
You choice of weapon layout is probably suboptimal, too. Unless you have a couple of those MCs engineered for incendiary, you're probably working on the NPC's shields longer than you should. The general rule is: Thermal weapons for shields, kinetic weapons for hull.
I did my early combat stints in a Chieftain; it's very nimble and has a good hardpoint layout, and can be somewhat tanky, if a little weak on the shield side. The Krait II is also very good, as it is very tanky, has a huge distributor even unengineered, and three large hardpoints do a lot of damage.
A Krait does a lot of damage with three large MCs and two medium lasers; I prefer beams, and an engineered Krait distro can handle that, unengineered I would probably fit pulse lasers.
Some say the Vulture is a must for the up and coming combat pilot, because it teaches you how to glue yourself to the behind of other ships. The drawback is it has only two hardpoints (although two large do a lot of damage) and it's pretty power starved. But it's a fun ship to fly.
The best way to build a combat vessel depends on the engineering and materials you have available; maybe elaborate on that. Personally, I prefer hybrid tanking with very strong hull and at least two MRPs, preferrably three, and the largest quickest bi-weave I can fit. Never skimp on MRPs, more so on ships with fragile or exposed canopies. I usually fit one MRP in the largest slot I can fit one in, and one or two in the smallest slots to get the resistance up. Never put our largest MRP in a military slot.
Remember that rebooting is your friend. Unless you start a fight or have cargo, you are not getting attacked in a RES site; so when you're done with a fight and your shields are low or down, come to a standstill and reboot your ship. This will restore your shields to 50%. I think it doesn't restore the shields when you're moving faster than a certain threshold, but I can't remember the number.
When dogfighting, you need to anticipate your opponent's movements and try to preturn into their maneuvers, more so if your opponent is more nimble than you, like when you're in an Anaconda. In general you want to try to be glued to the back of your enemy, but that doesn't always work. Also keep in mind that a lot of NPC builds use turrets, so they can shoot at you at very odd angles.
And last but not least: Your rank progression is tied to the rank of the enemy. The higher your opponent's rank, the more rank progression a kill gets you.
On this wiki page is a handy table that gives you the factors of XP gain for different NPC ranks. I am pretty sure you get no progression if you kill an NPC of lower rank, I don't know why those were all changed to "?" in the wiki (the wiki can be bogus sometimes).
Hope this helps.