Going from skirmish to full list

[Sideburns]

So, we started playing Skirmish and I like this game... 

That being said how should I advance beyond skirmish level

Right now I have:

1 Freeguild General mounted with Great Weapon

1 Freeguild General on foot (magnetised to hold various stuff)

10 Freeguild handgunner

10 Freeguild guard (sword and shield)

What would complement these to make a 1000 points (and beyond...)

[Fisherdwarf]

I'm fairly new to the game, so please take my advice with a healthy amount of salt. However:

Freeguild/Free People have a few army archetypes you could build towards. Your choices will be heavily guided by the kind of army you want to play. I'll give you a few pointers, though.

Generally, Cannons fit well into our army. Artillery gives you a punch that can take out key targets or soften up units for your troops. You can get the Ironweld Arsenal Cannon or, if you'd rather go human, the compendium Empire Cannon (get it on eBay). Other artillery like the Helstorm Rocket can also be used to devastating results, but just one Cannon can do good work.

Wizards. A Battle Mage or a Celestial Hurricanum can give you a huge edge, throwing even more buffs on your already synergizing troops. 

Troops. You're going to need more bodies. Free Peoples is generally not a very elite army, so you should look to expand your units. I'd recommend running Guard in units of 30 or 40 (especially with cheaper hordes in GH2017). You could also either get more handgunners to secure their bonuses or, alternatively, you can get a bunch of crossbowmen and drench your opponent in bolts.

Knights are relatively hard to get a hold of and are considered fairly weak. If you do want to play a faster, more elite army, play your knights as (the formerly Bretonnian) Knights of the Realm, they are a lot better than the old Empire Knights (although not as cool looking).

Lastly, a General on Griffon is an awesome model and centerpiece in an army, and gives you a pretty powerful monster to wreak havoc with.

That's all I can think of off the top of my head. If you have any other or more specific questions I'd be happy to do my best to answer them. For Sigmar, yo.