Vacuum regularly, high and low — particularly sheltered spots such as beneath worktops, backs of cupboards or under/behind large furniture.
Remove noticeable webs — on a regular basis.
Fill in gaps — in walls, around pipework and under doors to deter entry.
Remove sheltering sites — like firewood piles, garden bags, compost piles and general clutter from near your property.
Deter all insects — use lighting in a way that is less attractive to the insects (flies) that spiders feed on.