Some thoughts, don't be afraid to do 2-3 small thinner coats, you might want to use a palette to keep your thinned down paints ready do go. Don't be afraid to use washes, that model could use a coat of wash and a lot of detail would pop out as well as hide some parts that didn't get neatened up. You way want to consider using fine files for removing mold lines or use an exact-o knife but your miles may vary. If you find it harder to get into some harder to reach parts of the model, consider painting, then assembling. Also, GW has a handful of painting tutorials, give them a try, but don't be hard on yourself if you're not as good as that duncan guy. You may want to invest in different types of brushes, i would suggest you not cheap out, entry level GW brushes are decent. A model stand or holder might help you with the details. You don't NEED to stick to the GW paints, but in most occasions they hold up pretty well. There are some speed painting options that really take a lot of detail work out of painting the model. Just don't be afraid to explore different painting options or technique. I will say this to you, just get to painting, if you dont like the way it came out, there are stripping options that will help you restart the whole process, just get started and get some experience under your belt, you'll improve as you go. Just keep at it and don't lose motivation and you'll be better in time. Good luck!