You could try increasing your workout intensity. There are a few ways you can do this: you can decrease the amount of time you rest between sets, increase the number of reps in your sets, or you can implement a variety of shocking techniques.
If you're wanting to switch things up a bit, a good way to do that is to employ one or several of these shocking techniques.
Some of the most popular intensity techniques out there include:
1.) Priority Principle - Essentially it means working your weakest muscle group first, or in this case, whatever aspect of your training you are stuck on. Also, hitting your weak spots hard after your rest days can prove useful when you're all rested up and ready to go at full force.
2.) Supersets/Trisets - Two or three exercises performed in a row. This technique requires more effort and energy, but the payout is that you decrease workout time, increase muscular endurance, and you can work opposing muscle groups back to back (chest then back, biceps then triceps, ect.) to really stretch those muscles out. There are some obvious drawbacks though, such as slightly decreased intensity for the second and/or third exercises.
3.) Pre-exhausting Technique - This technique involves pre-exhausting a certain muscle group before you work another. For instance, when you do bench presses, you're most heavily recruiting from your pectoral muscles, but you're also recruiting your deltoids and triceps to a great extent. By pre-exhausting the assisting muscle groups (such as doing a deltoid or triceps exercise right before your bench press), you're taking those supporting groups further out of the equation, allowing your primary target muscle group (the pectorals in this example) to do the bulk of the work without getting too much help from the other muscles.
4.) Weight Stripping - I'm sure you've seen this being done. It's where you start a set with however much weight on the bar, and as you go along in the set, as your muscles get tired, your training partner strips some of the weight off of the bar, which allows you to keep going. You see this a lot with biceps exercises, but it can be applied to anything that allows you to do it.
5.) Ballistic Training - This involves explosive effort while remaining smooth and in control of the weight being driven. This method of training creates variable resistance and is great if you're wanting to increase intensity. I just wrote out a pretty detailed description of ballistic training, so you can search for that if you want.
Those are just a few of the more popular intensity techniques you can try or read up on. If you have any more questions about any of these techniques, feel free to ask, or go looking around yourself for more info, because there's plenty of information about all of these techniques floating around on the net.
Also, as far as resting 5-10 seconds between sets... I wouldn't recommend it for you at this point. I'd say a good time to shoot for, if you're wanting to decrease time spent between sets, would be between 30 seconds (minimum) and 1 minute. I usually shoot for 1 minute, but sometimes go as much as 2.
As far as your leg workout goes, just make sure you include squats and a hamstring exercise, such as leg curls. Stiff-leg deadlifts also work great for the lower back and hamstrings. You can also include other compound lifts such as lunges and leg presses, which allow you to use heavier weight. I hope other's give input on leg training, but here's one example of a basic leg workout. And you can adjust rep ranges if you want, and sets...
Squats 4 x 16, 12, 8-10, 6-8
Lunges or Leg Press 4 x 16, 12, 8-10, 6-8
Leg Curls 4 x 16, 12, 8-10, 6-8
Stiff-Leg Deadlifts 3 x 10, 6, 4
Standing Calve Raises 4 x 12-15
Seated Calve Raises 4 x 12-15
Make sure you're keeping strict form on all of these lifts, going through a full range of motion every time, never sacrificing good form for more weight. And that's just an example of a basic leg workout, so look around and try different things so you see what works best for you.