Things you can do:
1. BAL X-chocks will reduce most of the fore/aft movement, but not all.
2. Install stabilizer struts as mentioned in above post. Depending on how many and how you install them, they can reduce side to side and fore/aft movement quite a bit and even a little vertical movement. We have BAL Lockarm struts because you can buy them as a pair only. I mounted them to the underside of our bumper which reduces fore/aft and side to side movement. The 1st photo shows how I did ours.
3. Use jacks just ahead of the axles under the I-beams. These can be bottle jacks, aluminum stacker jacks or scissor jacks. Some have welded on scissor jacks.
4. Use aluminum stacker jacks (or equivalent) at each of the 4 corners of the frame. The problem with the stacker jacks is that they aren't tall enough when extended and you need to use cribbing or blocks to build them up. I tried them and find they are too slow to set up and didn't help much. When using a 3rd pair of jacks like this, sometimes the ground can settle unevenly and result in a jack becoming loose.
5. Install Torklift Glowsteps. With ordinary foldout steel steps, there is a lot of leverage that causes movement. The Glowsteps make a HUGE difference. I can now sleep in when DW gets up early and goes for a walk. See ours in 2nd photo.
I haven't installed stabilzer struts to the front elec. stab. jack yet because we're now at a point where movement is reduced enough to make it acceptable. I may add them at some point when I've run out of other mods. to do. Tongue jacks can move around quite a bit. I've often wondered if support was added to the underside of the A-frame if that would reduce motion much. I think I'm going to try that one day.
With some TTs, the frame is simply more flexible than others and there's only so much that can be done. Also, some floors have floor "joists" too far apart, subfloor material that is too thin for the spacing of the joists and/or joists themselves aren't strong enough. Just walking around inside a weak floor can make it move around a lot. Friends of ours have a TT like that.
Go take a look at your elec. stab. jacks while someone walks up and down the steps and you will be amazed at how much they move around. They don't really stabilize a whole lot and regular scissor jacks are better. Stabilizer struts can help a lot for either type of jack.

