The synths are catchy, the beats are interesting and the vocals are filled with sexual innuendo - but nothing seems to mesh!
Here are some tips on how to make your mixes mesh more...1. One at a time
I've noticed a lot of beginner producers have everything blaring out and try and mix from there - you'll find it a lot easier to mute everything, then bring in each track one by one, mixing everything as it's added in.

2. Flat Response Speakers
If you can, grab yourself some speakers with a flat response - this means that they don't emphasise any frequencies. For example, Hi-fi systems with subwoofers tend to boost the bass, so if you mix on them you'll find your mix is drowning in flabby bass! Not everyone can afford these, however so the next best thing is to...

3. Get in the car!
Try your mix out everywhere. In your car, in someone elseĆs car (make sure you get permission, you can get in a lot of trouble otherwise), on your desktop computer, on your laptop, in your headphones - everywhere. You'll get a much better idea of what the song sounds like through a bunch of different systems.
4. Time out!One of the most valuable bits of advice - if you've been mixing for hours and hours, STOP. Come back in a few days - your ears need the rest so they can get some perspective! You'll find you notice problems a lot more quickly and easily if you don't try and do it all in one go.
5. Doctor! Can I get a second opinion?
Firstly - if you didn't instinctively think of Dr Dre as a producing doctor, minus 10 cool points for you. Secondly, you can get those points back by asking a friend for their opinion - someone with no musical background and no qualms with being brutally honest is great in this situation, just sit them down and ask if they think it sounds professional.
If they do - sorted. If not, then after crying about your hurt feelings for the next week, ask them what sounds out - try and help them with some suggestions if they're struggling since chances are they won't instinctively be able to say "The kick needs EQing to reduce the muddiness around the 100hz mark".