Re: Having hard time landing my jabs.
You should try working on the mitts and on the bag and shadowboxing with doubling and tripling up on the jab. Get to the point where you can just pump them out quickly without even thinking about it. Before you even get to that point however, I can guarantee that working on doubling and tripling up on the jab in sparring will eventually lead to the correct results.
Also, ever think that you might be projecting it a little? Maybe you could focus on disrupting your opponents rythm a little by moving your body and jabbing at very different speeds. I think it all comes down to being comfortable with throwing the jab while moving in a lot of different directions while aiming in a lot of different places with varying modes of speed in power. The more you practice the jab, the more that happens and as it does happen you will eventually notice more and more opportunities to land the jab.
Once you can really work it, I think the jab is probably the easiest punch to land in boxing.
Also, just to work on pumping it out, watch chad Dawson training. When he shadow boxes he throws his jab beautifully.
It also helps to watch a lot of different pros because a lot of them get really good at throwing the jab in one particular way. Pernell Whitaker is really fun to watch when he steps inside of his opponents left foot and lands a quick jab inside.
Sonny Liston is really good at getting low and throwing a jab up at the chin of his opponent. He broke the jaw of the "real rocky" with that punch. He also throws it a bunch (often unsuccessfully but still really well) in his first fight with Muhammad Ali.
Andre ward is fun to watch the way he pumps his jab particularly when he faught Arthur Abraham and he kept pummeling him with his jab through his guard.
Sugar ray Robinson has a great upjab (jab thrown from hands down). You can see him use it really well in any one of his fights against jake Lamotta.
Also hit the double end bag a lot with the jab. It helps a lot with timing and it does a lot of good particularly with shorter fighters who like to move their heads and get low to rush you and get on the inside,