The process of making monolingual TSCs for grammar and vocab is the same because there's no significant difference between the two.
When you're reading books, watching things with subtitles, browsing the web, you're going to find sentences where you know everything in a sentence but one grammar point or one word. Take that whole sentence, put it on the front of your SRS card. On the back you're going to put the monolingual definition for the grammar point or word you didn't know.
- Download and install monolingual dictionaries for GoldenDict, Rikaitan, etc.
- Keep JMdict enabled (but hidden) for times when your monolingual dictionaries don't pick up certain words. Monolingual dictionaries tend to be smaller than JMdict.
- Mine sentences as usual, don't add English definitions to your cards. Having both English and Japanese definitions is acceptable only during the transition period.
You will run into grammar points that only have English definitions. Rely on Rikaitan to pin-point the grammar pattern, then use Weblio, sakura-paris or any search engine to look it up. Searching the web should lead to explanations in Japanese.
Also try monolingual dictionaries for grammar. They cover additional topics and can help when other dictionaries fail.
Some people would prefer to install as many monolingual dictionaries as possible to cover even more ground and minimize the need to look up words online.