I would suggest that you get a swim coach or at least look into some swim programs. The only way to get faster is to train fast. By that I mean doing sprints at 100%. It can be made as simple as doing a 50m sprint every 200m or so.

Don't worry too much about the swim though if you have already done an olympic distance as it is only 400m further for the HIM!

Swimming is all technique if you wanna be fast you have to learn right...

I disagree that the only way to get fast is to swim fast. In swimming, technique accounts for far more than conditioning. I'd try to find a good swim coach who can look at your technique and make sure you don't have anything that is really holding you back there before piling on the yards. Also, since water incurs so much more drag than air, any poor technique can quickly lead to injuries, especially with higher yardage workouts.

Generally, if you're in the top 10% of a triathlon pack, you can probably benefit from intervals, sprint work, etc. If you're farther back than that, I'd bet that technique is a bigger limiter than swim conditioning.

If you're ready for intervals, for half-IM or longer races, I tend to focus on distance-based intervals, 300 yards and longer. So 10 x 300 or 8 x 500, or 3 x 1,000 yard intervals, generally trying to get faster with each repetition (with the longer ones, like 1000's) or get faster in groups of 3 -4 with shorter intervals. So 10x300 would look like:
slow, med, fast, slow-med, med-fast, faster, med, med-fast, fastest, slow (to cool down).

Here's another good main set, from my coach this week:

800, 7x100, 600, 5x100, 400, 3x100, 200, 100 (you can either work the long sets, or work the 100's, depending on what you're aiming at with this workout.)