Dzsono: Um, I have no modding skills
That I find hard to believe.
Let's see what categories one can help with.
1) Coding. This does require some C++ knowledge, but code is quite readable. There are also people willing to help with code problems
2) Items. Biggest pain is the images. If you can create good looking images, you can add items to the game.
3) Tilesets. Not the same as items, but quite close. While items refer to inventory items, tilesets refer to map items (tables, chairs, doors etc). Again, images, though there is a bit of structure that has to be done (wouldn't want a brick wall bullets ignore now, would we?)
4) Portraits. Images again, along with a bit of animation. JA2 has a quite distinctive style, but new faces are always welcome.
5) Voices. Grab a mike, ask for a spreadsheet with a merc's lines, and record your own. Extra voices (especially for IMPs) are more than welcome. There are also a few bigger mods that are always looking for voice actors
6) Mapping. Smeagol and Zombiehunter seem to be the active mappers at the Pit atm, but if you can map, you will be one of the highly praised members.
7) Writer. We need taunts and hints. Assuming you have a recent copy of 1.13 (aka not 4870), take a look at Data-1.13\TableData\EnemyTaunts\EnemyTaunts.xml and Data-1.13\TableData\LoadScreenHints.xml
There are probably a few more things you could do and be able to contribute to the modding of 1.13, it all boils down to how much time you can afford to contribute :)