I must confess, I have only one fully painted army (my vampire counts). My orks are about 30% painted. I had planned to get about 2000 points finished before the new codex drops eventually, but they have been off the painting table as of late. My tau are about 25% complete. They are a simpler paint scheme and I was able to base coat most models with an airbrush. I even started an escalation painting league to help motivate me to finish the army. Yet still I failed.
Recently I have started my Iron Hands, they can be seen here. I got through there first tactical squad and rhino (I finally got a top hatch for it btw) in about 2 weeks. I have literally been painting one marine at time to completion before moving on to the next. Right now, this feels like a comfortable pace for me, but I am all too aware that I have failed before.
The only tactic that seemed to keep me motivated to paint was what I used with my Vampire Counts. I would not let myself buy another box until I painted the previous. It worked well, and I didn’t play fantasy often. I just haven’t been able to exercise that level of self control with my purchasing of 40k.
I may not have succeeded in painting a 40k army to completion yet; but I have read about many different strategies to keep one self motivated. I figured I would give you a short run down and my experiences with each.
1) Batch painting. The idea is to take a large batch of models (10 or more usually) and paint one step or color at a time on each model before moving on to the next. I discovered this tends to work well on units with very uniformed models and simple color schemes. It did not work well with my orks. There was far to much variation in how each army, boot, gun, ect had to be painted to fit my paint scheme. This led to a lot of missed spots that I would have to go back on to fix. Slowed everything right down. It did work well on my tau though, since the models are all very similar and the paint scheme is very simple.
2) Small Batch painting. Similar to above, but small groups of models. I found that 3-5 work best for me. This is how the majority of my orks get done. Probably the most common method I use.
3) Painting on a schedule. The idea being to set goals in terms of a calendar. Like I need to finish the squad by the end of the month. It all works groovy until you either A) get behind because life invades hobby time, or B) you work on a model or unit you don’t enjoy. Then you are either forcing yourself to do something you are not enjoying or rushing through to try to catch up. This happened with my tau crisis suits, and I feel the rush to get done had a noticeable drop in quality.
4) Painting individual models. Idea is to only paint one model at a time, allowing for more detail and focus on each model. Results in good quality, but is a very slow process. Better have some good pod casts or Netflix lined up. I recommend the overlords or the independent characters.
5) Painting a unit before buying the next. See above.
In the end though, the best thing I can say is just keep painting. Do a little bit here and there and it will all add up. I get bored painting one unit, so I will switch to another unit or a whole new army. Yes, it takes me longer to finish things this way. But painting should not be work, it should be fun.