This is the simplest technique and should be the first approach you try. The rule is very simple - any star cannot have another star touching it so for any placed star the 8 cells around it can be immediately marked with dots to exclude other stars.
After a while this should become instinctive and the surrounding dots can be filled in every time you place a new star, or if playing interactively you can enable the auto dots feature to add these.
In the example, the central star has been placed (it's a single cell region so must be a star). Each of the surrounding 8 cells around the star can now be excluded:
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