This might be a good place to check for some recommendations:
Personally, I get really bored by Genki, so for a long time I’ve avoided it. I do plan to go back through it sometime to refresh myself on stuff, though.
And for a free resource that’s good, especially for getting used to grammar, there’s Tae Kim’s Guide to Japanese (you’ll want to look at the grammar guide portion of the site specifically).
I highly recommend checking out the forum’s compiled list of recommendations linked above, though. There’s a lot of good stuff to check out.
As for how I use these and other resources, I don’t have too many pointers. For a long time, I used Anki religiously to study sentence patterns, and I do think that helped me. Certainly, starting out reading baby-level graded readers and working up toward more difficult material also helped me get my bearings to read Japanese material.
Being able to produce your own sentences and express more complex ideas are some of the most difficult things to do, I think, when learning a language, so study and keep at it for sure! But I would recommend not being too hard on yourself if you’re finding that your speaking/writing ability lags behind reading and listening comprehension. Practice certainly helps. I’ve seen lots of folks on here recommending HelloTalk to find speaking partners in your target language, so you could try using that.