Construction
Spend your early gold coins on the Dragon's Lair and then on Sky Babylon. The Electric Rod corresponds to the props from the Dragon's Lair except the gold coin. You can't get a gold coin through the Electric Rod.
As for the silver coins, I went with putting ten levels into the Forest, then five into the Collection Field, going back to add five more to the Forest, then five to the Collection Field followed by the first five into the Remains and following that pattern until I had about 2000 income.
For easier visualization:
or
or (yes, the screenshot is from later in the game as I missed taking one early on having remembered the possibility of a screenshot only later, but shows the system I mean all the same)


Props
Use your +Intimacy Props quickly or you'll get swamped with them. There's no need to save up more than a few as you get them as Level up rewards. Also there's no way to use multiple of the same Intimacy Prop at once, so consider an autoclicker if you have a lot of them.
The -Intimacy only applies to the Intimacy of the current level, so when you're only 10 Intimacy in the level it will only cost you those 10.
There's a little glitch that could come in handy with the +Intimacy props. If you use a prop that immediately gives you a reward level with a prop that you have none of and appears just before the one you're using in the order of intimacy props the one you are using won't be consumed but one of the rewarded ones will instead while still giving the benefits of the one you actually used.
For example you use a Green Paprika while having no Apples, which makes you gain level 10 your Green Paprika won't be consumed, instead you get only 9 Apples instead of 10.

Here I list how many PAs you can get through the different means, which includes light spoilers.

There are 39 creatures you can get from Orange Boxes.
There are 7 creatures you can get from Origin Boxes.

There are a total of:
32 Level 20 Evolutions
15 Level 30 Evolutions
2 Level 40 Evolutions
When leveled the amount needed for the max level achievement, the level number becomes yellow, the required level is 20 for a lot of the PAs that evolve through hitting a specific level. Though some also need to reach level 30 with few needing 40.
The final evolutions need max level 50 each.


There are only a few evolutions you can get through items.

Hints:
The fly likes food.
Felines can have many different colours of fur.
The robot require a different kind of sustinance.
Flowers enjoy company of their own kind, but don't let the colours fool you.

Solution:
24: Suckfly LV: 20 - Hamburger + French Fries + Chicken
40: Cat LV: 30 - Yellow Claw + Red Claw + Blue Claw + Green Claw
84: Chessant LV: 30 - Particle + Photon
91: Jasmelf LV: 20 - Jasmine
93: Mandelf LV: 20 - Mandala
95: Crapelf LV: 20 - Safflower
97: Buffy LV: 20 - Daffodil

If you want to play a seperate game while having this one play in the background, start the other game first. If you start a different game with this one already open it will crash.

On the following probs:
Card of Spirits
Reformers
Dark Flowers
I have no idea what those do other than factor into one achievement. They seem to simply refer to other games of the publisher.