Were they more medieval or were they closer to the Revolutionary War? Were rifles the most commonly used weapons or was it still bows, and maces? Were professional armies used or was their mass conscription?
Actual "battles" on the field was very rare in the Thirty Years War. the early to mid 17th century is widely seen by historians as a transitional period between late medieval warfare where cannons and other seige weaponry had just been introduced and the mid 17th to 19th century when the bayonet was introduced and firearms became more precise and deadly. Infantry during this time was mostly made up of Musketeers, Pikemen and Artillery in varying formations. Most of the warfare during the Thirty Years War consisted of seiges, seiges and more sieges. Real battles like at Breitenfeldt or Lützen were a rare sight, and when they happened they were bloody, smoky, confusing affairs - even today historians are still arguing about who really won at Lützen. Soldiers during this time had no common uniform either so you better have a good idea about who and where your guys were.
As for weapons, everyone had firearms and projectile weapons like muskets, pistols, arqebuses, cannons and mortars. Pikes were also extremely important and it is the reliance on the pikes and muskets that has given this era of warfare the name "Pike And Shot". Nobody used maces but bows were actually carried into battle by the Scottish Redshank mercenaries, probably not to any great effect. Swords were mainly close combat weapons but the Swedes used the Sword as an offensive weapon in their Cavalry charges. Common practice in a Cavalry charge had until that time been to fire your pistols then strafe around to let through the next line of riders who'd fire their pistols and so on - a manoveur that was known as a "caracole". The Swedes would fire their pistols, draw their swords and lay into the enmy ranks. Another edged weapon that was used during this time was the "Partisan". A spear like weapon mainly used in the defense of fortresses and the like.
Armies during this time were also mainly made up of mercenaries who often didn't even care about who or why they were fighting and would switch sides depending on who paid better or where they could loot. Along with the army there would also be a mess of camp-followers, prostitutes, soldier-wives, children, hucksters, hustlers and refugees. All of these people had to sustain themselves somehow and this mean raiding and pulndering wherever thay could. A good eye-witness description of how a day in the life of a soldier in the TYW could be is the diary of Peter Hangendorf, wich unfortunately is not available in English.
So in short, the TYW was fought in a period of transition between old and new warfare. It is not comparable to the Revolutionary War at least not on any deeper level.