Swing feel depends on a lot more than just the rhythm of your 8th notes. Subtle accents created through tonguing are an important part of the groove too. Articulation also helps lock in the time of your lines. Following are some guidelines for adding articulation to your 8th note lines.
1. In 8th note lines, tongue the "and" or second 8th note in each beat and slur to the first 8th note of the next beat.
2. Tongue the first and last 8th notes in the line. Make sure to cut off the last 8th note with your tongue. I like to use the syllable "dat" to approximate the sound of the last 8th note because it starts and ends with the tongue.
3. Tongue and give a little more emphasis to the peaks, meaning the high notes when the line changes direction. The peaks of the line are marked in this example:
You can see two of the peaks fall on the beat, which means tonguing just got a bit more complicated. The articulation would look something like this:
In some cases, saxophonists ghost or significantly mute the note right before the peak, particularly when it's a lower note that leaps up to the peak like the E on the and of 4 in the example (the parenthesis around the note mean it should be ghosted). The way that most of the great saxophonists of the past accomplished this was to use a doodle tongue to ghosted or mute the note. Essentially, doodle tonguing is when you gently put your tongue slightly off-center on the reed, letting the note still sound. That creates a muted sound, and when you take your tongue off the reed it creates an articulation or even an accent. I use this technique for articulating the peaks that fall on the beat, and you can hear guys like Bird, Cannonball, Rollins, Trane, and Potter doing the same thing.
4. Beside the end of the line, tongue the other arrival points that break up the line.
Above, it's an 8th rest that breaks up the line, and a quarter note would be treated the same. Any other note or rest that breaks the 8th note line would also be treated the same.
5. Despite all of this tonguing, there should be a generally legato or connected feel. Except for rests or the occasional staccato (think Rich Perry), there shouldn't be any break in the sound before each tongued note. This can be challenging to learn to do, but listen to all of the best jazz saxophonists and you'll hear that the connected sound is a vital part of their lines.
Incorporating all of this can be daunting. Start by picking a transcription, one you've already played if possible, and marking the articulation. Then listen to the recording and try to catch anything you've missed. Then practice the transcription, working on getting your articulation to sound as much like the recording as possible. The more careful listening you do the easier this will be. Bebop tunes also work really well for this kind of practice.
Additionally, you'll want to practice your own lines, adding in articulation. I'd suggest improvising a line, writing it out if you need to, and then adding in the articulation. As adding articulation becomes more intuitive you'll be able to just practice improvising in real time, correcting your articulation as needed. Good luck!