Battle Nations!: Tips for a beginner

Battle Nations

This game is my current obsession and because of how much is packed into it, might be for a good long while. What makes me so sure of this, is that I've been playing it for a good two years now. It's that long. About level 42 (meaning of life) now. Rambling.
Back to topic. As I play Battle Nations now, though, I've found the need for XP is a reoccurring problem for players later on when the needed amount increases.
 The main source for XP comes from the shops and the jobs they offer. I've done several experiments with the buildings XP yields and Have found mainly two non-premium and low-leveled buildings that yield a high amount of XP: "The Boar Pen" and the "Field". Both yield a decent amount of XP even from the low tier jobs, giving about 100 XP at a time. But to get the best out of either of these, you need to know your preferences. The boar pen, though it yields a large amount of XP, has jobs that take twice as long as the fields. It is because of this time difference that would make using either of the two difficult. So if you only check on the game every so often I would recommend just going with the boar pen, but if you're like me, someone who checks on the game very often, go with the field.
There are also some decors that would provide a bonus to XP. Because the nature of the two buildings I have mentioned though, the two need different items. I will provide a list of the items I currently use on mine.

Field:
-Black Top Roads x6
-Silo
-Water Tower

Boar Pen:
-Black Top Road
-Silo
-Feeding Silo

By using these decors, you can boost the XP by at least, 40%. Though these decorations cost a bit of resources, it is worth it, I highly reccommend it.

Using this strategy, I've managed to level up fairly easily, only taking a week or so rather than a month as usual. Look, level 42 easily.