You may notice that in some of the pictures the shields of the models get painted without any info on how this was done. The shields didn't turn out how I had hoped, so I have decided to go back and do them again. They will follow along in due course.
One quick tip I have is to keep a spare brush on hand. If you make a mistake and get a spot of paint in the wrong place, wet the spare brush, shake off some of the excess water and quickly wipe the paint away. You may not get 100% off, but it's usually enough to hide all but the most terrible of errors. If you have painted a large area in the wrong colour you're usually better off letting it dry and going over it again later.
If you find colours showing through your paint from underneath, wait until the model is dry and then go over it again. Yellows, Reds and Whites are terribly transparent colours and may need a couple of coats. It's usually better to thin your paint slightly with water or a tiny drop of medium to help it flow better rather than to keep dolloping paint onto a mini. Wash your brush in water regularly and wipe it on a paper tissue, then rinse in a clean pot of water. Once it is clean, repoint the brush by cupping your hand and gently turning the brush back and forth in one of the folds in your palm.
@M_i_J - You may want to look away now. The horrors that will be shown in this thread may offend your delicate painting sensibilities.

Step One.
Priming your minis.
Once you have your minis assembled, put them in a box and go outside with a can of spray paint. Give them a light covering with it. Once they are dry, turn them around and do the other side of them.

Step Two.
Metal parts.
Viking and Saxon minis feature a large amount of chain mail. It's easy to get this over and done with asap as they have belts and suchlike on top of their armour. You can be as messy as you want at this stage, just make sure you cover all the armour, helmet, shield boss (the round part on the front), blades, spear points and sword hilts.

Step Three.
Metal wash.
Once the metal work is dry, go over it with a black wash. Brush it on and avoid letting it pool up. In this picture the model on the left has been washed, but the one on the right has not. Again you can be fairly messy.

Step Four.
Trousers.
With the metal work out of the way, it's time to work on the clothing. Uniforms were non-existent at this period in time, so you want to avoid painting all the clothes the same colour. I use a 'rule of 3' for making minis look different without adding too much work. Choose 3 colours which you will use for each set of clothing and divide your minis into 3 roughly equal batches. Do each batch in one of your 3 colours.
At this stage, paint the trousers and the underside of the tunics. You don't need to be too careful, just try to avoid any of the metal parts.

Step Five.
Wood.
Moving over to a different part of the minis, paint the rear of the shields, weapon shafts, sword hilts and the like in your chosen wood colour/colours. Again, you don't need to worry about being neat so long as you are careful when working around the parts you've already done.

Step Six.
Tunics.
Back to the cloth again. This time do the tunics around the waist and the arms, being careful now to avoid the armour and trousers. Again I have gone for a rule of 3 type approach. Mix your minis together and divide into three new batches, with a mix of trouser colours in each batch. Now use three other colours for the tunics. This should give you 9 different colour combos, more than enough for the wild and disorganised dark ages. Make a note of which colours you use here.

Step Seven.
Leatherwork.
Using a medium brown colour, go over the scabbards, shield rims (front and back) and shoes. Take care not to miss any of the small daggers or other accessories you may have added to your figures.

Step Eight.
Belts.
Using a different shade of brown, go over the models carefully and paint in the belts and straps on their armour. Most of the Saxon/Viking minis have necklaces on as well, so don't miss those. If you can't get at the back parts easily don't worry. Helmets and hair will mean that you can't see those parts from a distance anyway.

Step Nine.
Leg Straps.
Some of the models wearing trousers have strings tied around the lower half of their legs and some are wearing leg wraps. Paint these in carefully.

Step Ten.
Brown Wash.
Time to add some shading to these minis. Carefully paint a brown wash over everything that isn't metal. Don't worry if you do get some on the metal parts, they will just look dirty/rusty/covered in dried blood. As with the black wash, be careful not to let it pool up anywhere.

Step Eleven.
Tunics part 2.
Remember I said to make a note of which colours you used for the tunics? Get those colours out and go over the tunics again. This time you only want to hit the raised areas of the cloth rather than painting everything. The goal is to leave some of the areas darkened by the wash showing to give an image of depth and folds in the cloth.

Step Eleven B.
You can do the trousers and leg wraps in a similar fashion to the tunics at this stage if you want. I didn't bother because you won't see much of those parts of the models anyway and I'm a lazy good-for-nothing wastrel.
Step Twelve.
Shiny bits.
Get a small amount of gold or bronze and paint the icons on the necklaces of your warriors. You can also add some bling to raised parts of the helmets or the hilts of swords if you'd like. Don't go overboard.

Step Thirteen.
Bases.
At this stage, I started doing the bases, but you can actually leave them to the end if you'd like. I just did them here because I was doing some work with PVA glue anyway. Put a blob of PVA/White Glue/Bondo onto your pallet and paint it over the bases of the models with a cheap/old brush. Put it around the feet of the mini but try not to get it onto the mini itself. If you do, get a wet brush and wipe it away. Once you cover the base, dip the mini into some sand and give it a gentle shake. Again, wipe away any sand that is in the wrong place with a wet brush. Don't let it dry somewhere you don't want it. Leave the models to dry for at least 12 hours, if not more.

And now I'm getting tired. More to follow when I get time.
