First off, always clean before resizing. You don't want dirt and muck going up into your dies.
Second, I always deprime before cleaning, so I don't have to worry about the primer pockets. the Lee universal deprimeing die is great and only $12 on midway.
Third, when reloading 223/5.56, Separate the brass and the loads. 5.56 brass can have less case capacity and using a load worked up in a 223 case could result in pressures being too high in a 5.56 casing.
fourth, watch out for crimped primer pockets, you will need a tool to get rid of the crimp. RCBS makes a die to press the crimp out, and there are several cutters that will remove it as well. The crimp makes it almost impossible to seat new primers.
Fifth, mark your ammo. I use a sharpie and draw a line across the bottom of my reloads to mark them. This way I can tell the difference between factory and range brass, vs my reloads when I pick up.
Sixth. I don't know what trimmer you have, but you NEED a Little Crow Gun Works Worlds Finest Trimmer if you don't already have one. I have tried several trimmers, but for processing bulk rifle brass this is the way to go, worth every penny!
Seventh and Last. Case lube. You WILL need it. Take it from someone who has gotten casings stuck in dies a couple times. Most case lubes, even the home brews are good. Personally prefer a spray. I use the hornady 1 shot in an odd method. I take a 1gal ziplock bag and put in a couple handfulls of brass until the bottom of the bag is coated in about a layer to a layer and a half. I then spray it into the bag and shake it up give it another spritz and shake it again. Then I dump the casings out into a plastic tupperware and let them dry for about 15min. Then they are ready to resize. To me it is much easier then lubing each case individually.
My current process for rifle brass is
deprime
tumble in walnut 4hrs (I'm planning on getting a wet tumbler soon)
resize brass
swage primer pocket (remove crimp)
trim brass
deburr brass
(optional) deburr flash hole
load
Handgun brass is much easier (9mm)
deprime
tumble 4hrs
resize
(infrequently) remove crimp
Load