Any ruck marching tips?

I spent the first 12 years of my career in Airborne units. Rucking depends on the person. The only tips I can give are based on humping with mortars over all different kinds of terrain from the deserts of Iraq and NTC to the forested areas in Germany and JRTC to the mountains of Alaska and Afghanistan. Carry the heavy stuff as high as possible in your ruck. A lot of people load the bottom with heavy stuff which lowers your center of gravity and will cause your hips and core to get tired very quickly. Get a good pair of boots too. People spend way too much money on fancy boots that look good but do not provide any support (i.e. Nikes and Rocky C4 Trainers) you will want foot support. My last tip is to not run, ever. If you start getting tired and fall back people have a tendency to run to catch up. The speed you gain is negligable and will take more energy than the distance you will cover. Depending on terrain you can either take more smaller steps or, if on flat ground, swing your arms and stretch out your steps to cover more ground with each pace. If you still suck at rucking the best advice is to keep doing it. Don't worry about heavy weight, just get your speed up with less weight and gradually increase it. Basic ruck marches start with very light weight and progress to more as time goes on. I hope that helps you.

I enjoy rucking and do it at home for PT. It is a must to stay conditioned.
1. Your boots and socks will make a world of difference. You have to take care of you feet. I have always wore very thin like boots. Something like jungle boots. I actually only wore jungles when we had BDUs. But you need to find a boot that your feet be conformable in. I use the NIKE leather SFB. It is a great boot. In addition sock are huge. I thought they were overrated until I got a pair of Fox River socks. At 8 dollars a pair they are not cheap. But I needed up taking about 18 pairs with me to Ranger School. I made it the way time there with no blisters.
2. Change your sucks when ever you can. Let them air out if possible. Don't be that guy that wears his boots for 3 days straight. You will be destroying your skin and welcoming blisters. If it gets bad a foot fungus will reek havoc on your feet.
3. The way you wear and pack your ruck will make a huge difference. Pack the heavy items at the top and near to you back. It will wear better and your body will be better able to compensate for the weight. I only put my sleeping bag in the bottom portion of my ruck. And use the compartments. There is a divider in the ruck sack. Use it. The more weight the higher the better you will be. A poorly packed ruck will feel heavier and a well packed ruck will feel lighter.
4, Water proof and compartmentalize you gear. I use two water proof bags. One for each portion. I will also use ziplock bags to pack additional items on the outside of the ruck in the sustainment pouches. This will usually be socks and shirts. But don't just throw everything in your ruck. If you don't really plan on using it they tie it up and pack it. I use a rubber bands to help pack. Everything is rolled up and rubber banded. You will have way more space.
5. Go ruck. I would start at 40 and work you way up to about 75 for at least 6 miles.

Gold bond or anti-chafing shorts, pantyhose cut at knee. Change socks. Get weight over hips. Relax breathe and have fun!