Latvian grammar (see Latvian Grammar) is almost entirely about managing one big feature well: the seven-case noun system. Sequencing matters more here than in most languages.
These two cases cover subject and direct object — enough to build real, useful sentences. Treat the other five cases as later additions rather than trying to absorb the whole system before speaking a single sentence.
Dative (the "to/for" case) is easiest to learn attached to specific common verbs that require it, rather than as an abstract rule — learning it through real example sentences with a handful of everyday verbs makes it concrete rather than theoretical.
These cases become genuinely useful once your vocabulary is large enough to need to express possession, means, and location fluently — introduce them as that need arises in your own sentences, not on a fixed calendar.
Vocative (direct address) is the least frequently needed case in everyday beginner conversation — it's fine to learn it last and treat it lightly relative to the other six.
Since adjectives must agree with the noun's case, gender, and number together, practice adjective-noun pairs directly rather than studying noun cases and adjective agreement as two separate topics.
See also the reference page: Latvian Grammar.
Nominative and accusative — they cover the subject and direct object, which is enough to form real, useful sentences before tackling the remaining five cases.
Attach it to specific, common verbs that require it and learn it through real example sentences, rather than as an abstract rule on its own.
As your vocabulary grows large enough to actually need expressing possession, means, and location — introduce them as that need arises rather than on a fixed timeline.
No — since adjectives must agree with a noun's case, gender, and number together, it's more efficient to practice adjective-noun pairs directly alongside each case rather than as two separate topics.