What is a good way to increase N/W without gaining more land and military??

Tech

and money

No, tech is far superior to cash for gaining NW =P

Assuming you are a farmer. You need to spend your turns to produce bushels in order to have income.
So you spend your turns teching even tho you are not a techer? or you spend your turns on cashing?

if you're not gaining land or planning to get land in future, you should cash your turns :P

if you're planning on getting land a bit later (maybe?), i would build construction sites with my turns

Techers are the only ones who should spend their turns teching. Everyone else should be purchasing their tech, not producing it.

And why do you have a phobia about gaining land and military?

Since my acre/nw is currently in the low range compare to countries in my ranking range. Military increase my expense and i do think my military is consider high in my range. So adding addition militrary for the short term might be unnecessary.
But no matter how high your military in your ranking range you are, to someone much higher in rank you are still a good target due to your acre/nw been low (the 1st indicator you look when searching for target - fat land with low n/w).

New to the game. So do correct me if i am wrong .... Thank you!

You should be getting technology to boost your economy, not to boost your networth.
You should be getting military to boost your networth. If your landsize is higher than those with a similar networth to you, then either you lack sufficient production technology, or your military is too weak. Unless you play a casher, you should get accustomed to having your income be negative each turn due to the size of your military.

1st thing landgrabbers do when searching tgts is like you said high land and low nw (its earthers besetting sin after all these years, especially on rep cashers).

If you're a farmer, you need land.
If you're a casher, you need land.
If you're an indy, you need land.
If you're an oiler, you need land.
If you're a rainbow, you need land.
If you're a techer, you don't need land.

If you're not going techer, then you really need land lol.

Techers need land too, the more the better. Dont be fooled.

techers need land and alot especially those who will do mbr.

Everyone needs land

*takes legion's land*

How much land is ideal before stocking for each strat?

LOL

about 40K

no such thing as ideal since more is better.

at some point in each set the ROI of grabbing more land is negative, similar to exploring. The cost of the growth (cost to build, and turns waisted building) is greater than the benefit. this will depend on the strategy deployed, the cash per acre built and the turns remaining in the set.