In terms of establishing sacred space for a ritual, if you wish something more historical (not that there is anything wrong with modern innovations since any religion must change and grow to remain relevant) you can use the Germanic concept of land taking. To do this you take burning fire around the boundary of the space you are claiming. Historically this was done outside so it was a torch, but for modern purposes a candle can be used. You can ask Thor to make the space you are claiming to be hallowed (made holy).
This need not be limited to a circle, square sacred spaces are probably more common in the historical context. Also if it is an outside space regularly used for rituals, historically they put a series of posts around the space and hung ropes between each post, as a way to mark what is the ritual area. Also in regular outside spaces they piled up some rocks and any liquid items from the offerings got poured over these stones (blood, mead, ale, drink of any sort).
In the historical context any ritual sacred space is considered a frithstead. No acts of violence may be done within a frithstead, and all beings within the frithstead have to leave any conflict outside. Properly done ritual offering of an animal (animal sacrifice) is not considered an act of violence since when they historically did this correctly they did it in a way that the animal did not realize it was being killed, and in a painless way. Later the animal was used as food. Since most us modern people don’t raise our own animals and don’t know the proper ways to kill them for food, animal sacrifice is generally no longer done in modern Heathenism. Offering drink and already prepared foods is perfectly acceptable as an alternative.