What are the tank dimensions (length x width x height)?
What sort of light/s do you have above the tank and what is the Kelvin (K) rating on the globes?
How long are the lights on for?
Are you adding any aquarium plant fertiliser or carbon dioxide (CO2)?
--------------------
LIST OF PLANTS TO TRY
Some good plants to try include Ambulia, Hygrophila polysperma, H. ruba/ rubra, Elodia (during summer, but don't buy it in winter because it falls apart), Hydrilla, common Amazon sword plant, narrow or twisted/ spiral Vallis, Water Sprite (Ceratopteris thalictroides/ cornuta).
The Water Sprite normally floats on the surface but can also be planted in the substrate. The other plants should be planted in the gravel.
Ambulia, H. polysperma, Elodia/ Hydrilla and Vallis are tall plants that do well along the back. Rotala macranda is a medium/ tallish red plant that usually does well.
H. ruba/ rubra is a medium height plant that looks good on the sides of the tank.
Cryptocorynes are small/ medium plants that are taller than pygmy chain swords but shorter than H. rubra. They also come in a range of colours, mostly different shades of green, brown or purplish red.
Most Amazon sword plants can get pretty big and are usually kept in the middle of the tank as a show piece. There is an Ozelot sword plant that has brown spots on green leaves, and a red ruffle sword plant (name may vary depending on where you live) with deep red leaves.
There is a pygmy chain sword plant that is small and does well in the front of the tank.
--------------------
IRON BASED PLANT FERTILISER
If you add an iron based aquarium plant fertiliser, it will help most aquarium plants do well. The liquid iron based aquarium plant fertilisers tend to be better than the tablet forms, although you can push the tablets under the roots of plants and that works well.
You use an iron (Fe) test kit to monitor iron levels and keep them at 1mg/l (1ppm).
I used Sera Florena liquid plant fertiliser but there are other brands too.