I am going to agree and disagree with the suggestions thus far, both at once.....
I have always hated being told you need professional studio grade headphones, ($100, 150, 300+) Good monitors ($150, 300, 1000+) a treated room ($500, 1500+) to get a good mix. Hate it. And must by my very nature challenge that assertion.
(And FWIW, I would suggest that as far as mixing purposes go, many so called "treated rooms" aren't really done right, and aren't really helping as much as one might think!)
First off, yes for truly professional results. Not questioning that so much. But, not everyone wants or needs that level of result. Many are hobbyists just doing this for fun and I would suggest that with a little effort and technique, you can get great
results with pretty low grade headphones, compromised monitoring and certainly- no treated room. That doesn't mean trying to mix on toy quality headphones, computer speakers etc. but having fun and getting reasonable results on economical gear? yeah! I think so and in fact, I do!
Worse yet, I have spent quite a bit on monitoring gear I barely use.....
First important step. Know your gear. That means first and foremost, listen to a bunch of commercially mixed reference material on your gear, whatever it is.
Headphones typically exaggerate the stereo field, exaggerate bass, exaggerate reverb, etc. Being very
familiar with that, and just how much, you get an idea of how your mix should sound on that set of headphones. This is true if you are using $40 consumer grade headphones or $500 studio grade phones.
Some people say you cant mix on headphones. Some of the people saying you cant, often do
mix on headphones I am betting.
. On other gear you are familiar with.
Make a copy of your rough mix. Play it in your car. You know what your car stereo sounds like right? Play it on your home stereo, your iPod, whatever you normally use regularly and are familiar with. Take notes. Go back to the mix project and make changes. Repeat again and again. Keep refining and learning. Study. Take breaks. Reference more commercial mixes. Guess what? Even if you have great studio monitors and a treated room, this is an absolutely mandatory step.
With practice and experience, you get better at this. It takes less time. And you get a better idea of what you really
need if and when you decide to upgrade.
And don't hesitate to check your mixes on the worst possible lowest common denominator listening situation. Always plenty to learn from that. I learned bits about mixing listening to my work via Soundcloud on a "smart" TV's built in speakers. Sounded like crap, and I learned from even that!
Specifically to the OP's question: Recommend better headphones? Yeah, maybe. But without the above, it wont help much honestly.