I would like to make space between parameters smaller in ArcGis Script tool. For example, in the image attached I would like to make the distance between two parameter Standard terrain and User defined smaller. These parameters are Boolean data type.
Your question reminds me of Positioning parameters in Python script tool dialog box? and, although I have not tested it, you may want to look into trying to use a stylesheet.
Such techniques are further described in this answer to Controlling Categories in Script Validation Tools - Expanding Groups By Default.