I've been working on a wooden structure to place my 6 solar panels in. Its almost finished, just a few pieces left and then wood treatment to help it last.

I'm concerned with the wind and what I can do to mitigate that danger.
The structure is on a lower ground as you can see in the picture. Behind the structure, the small "wall" and bushes help to break the wind a bit. On the ground above, there's a wooden shed which also helps with that.

Any other tips that dont include making cement footing for the structure? :)

Screw type anchors for sheds and temperary fabric structures can work. The structure looks light for ballast placed on the base as do the sloped vertical beams. 2x4 in short spans works well, 4x4 and 4x6 for mounts like you have there is best.

One thing i do for temp mounts with light framing or with wood generally, is to through bolt with shanked hardware. With heavy wood lags can hold for many years, but light wood in weather and screwed with light screws, will only last so long before the screw pulls out.

Joinery technique has to accomodate the materials. Some light sheetmetal gussets will go a long way for security and can be had free from scrap or bought. Plumbers tape comes to mind also.

Wind is a toughie on array mounts as is snow load, if you get snow and ice there.

I wonder if anchoring each corner (and maybe a few other places) to a metal star picket (fence post also known as Y post or T post) driven as far into the ground as possible might help. It would depend on what your soil structure is like though.

I watched them install a huge solar farm near me.   NONE of the posts were set in concrete.  They had special machines that simply drove the steel posts about 4-5 feet into the ground.

What I have done in the past is to dig a 2-3 foot deep post hole (like you would for concrete footing) and then set 4x4 posts in it and fill the hole with pea gravel.  Once you compact the pea gravel , it is almost as durable as concrete.

FWIW that structure will NOT survive any significant wind without being anchored some how.  Wind blowing over the panels will create 'lift' and flip it over.