While I'm not nearly as knowledgeable as the other posters, maybe my experience will offer encouragement.
I had "beginner" plants (java fern, anubias, swords, hygro) for over a 1 year my in aquarium, and while they never thrived they survived growing very slowly. Algae problems were dealt with by buying algae eaters. Mostly newly introduced plants would melt or be consumed by algae. I tried dosing with Seachem Flourish and upgraded lights. All I got was more algae and faster plant death.
After much resistance I started giving in...dosing with Excel, then root tabs, then liquid fertz, then CO2, then dry fertz. With each step I saw incremental improvement and I've finally reached a stable state where there's good, healthy growth with minimal algae. Results weren't instant, it always took 1-2 weeks to notice a change, sometimes longer for sickly or slow growing plants.
So let me confirm everything that others have said is absolutely true -- macro & micro fertilizers in addition to the CO2 and good lights are an absolute must.
This thread is a must read: _Dosing Regimes_