How long do you think I should stick to these routines? Also, should I consider bulking up? (other people have suggested I gain weight but I'm not to sure)
This question wasn't meant for me, but I felt like answering. Soccer isn't the kind of game where you would need mass. So maybe bulking isn't necessary. You are about the same weight as I am (74kg), so it's not an obstacle for strength training either. Stick to a routine for atleast 12 weeks. That's what I consider the minimun. After 12 weeks you'll know if the program is working or not. It doesn't mean you can't change the exercises inside, but the methods and movements should remain the same.
I play for a team that competes in tournaments throughout the year so we don't have an off-season. We usually have practice once a week and twice or thrice two weeks before tournaments -- Looks like I might have to do endurance training (intervals). I read a few articles about the creditably of interval training and a few people were saying it didn't work. Is this true?
What else could you do for endurance? Distance running only teaches your body to handle long distances, when it comes to higher intensities, it's rather useless. Intervals (either aerobic or anaerobic, I prefer the latter) develop the energy systems of your body. They can create, and regenerate energy faster, and your intake on oxygen for example might get better, and your body handles lactate better. Soccer might not be the best example, but also in soccer you are constantly doing intervals. Not one soccer game is steady-pace running from end to end. Not one.
Okay, fair enough. Aerobic lower intensity exercise has it's marks, but it's more in general health and well-being of a normal person. For athletes and sports I'd recommend higher intensity, aka interval training.
A: Protein - I know you said 1-2/kg of your weight daily but do you have any specific guidelines? Also, would I be eating a lot of protein during days that I exercise or should I have the same amount all throughout the week? I'm not a huge fan of meat, dairy and eggs but I know I can get a protein from a few other sources though I don't know if it would be enough (I would have to calculate it to be sure) so should I consider protein shakes? Also, most of the people I know associate protein with bulking up so is this necessary or does everyone in-general need that amount?
Actually no, I can't say any more specific guidelines. Protein intake is a very complex matter, and if you look around, there are different suggestions everywhere. Also it's also dependant of your goals. In this case it's strength and maybe a little bulking. You do a lot of exercising, so you need more protein. Strength training always needs heaps of protein. I would suggest somewhere along the lines of 1.5-2g of protein per kg of bodyweight. If you can't eat that much, no stress. There are very controversial material, many saying you can get along just fine with 0.75-1g/kg amounts. I would recommend eating about the same amount daily.
Protein shakes are good. Almost everyone here on this forum most likely uses protein supplements every now and then. Protein is important for building and repairing muscle and getting you recovered after working out. If you want to improve the performance, I would suggest you to consume protein in every meal, but especially pre and post-workout.
B: Do you have any specific guidelines? (links maybe?)
No, I don't. Again. It's not simple. People have different methods on carbohydrates and they all seem to work if you do it correctly. Some people (like me) cycle carbs: Off-days are low carb (20-100g), workout days are higher carbs with somewhere along 100-250g of carbs depending on lots of things. It works. But some people get 40-60%(up to 350g and more) of their energy from carbs every day and they are as good as anyone. Usually these people eat far less fat. You got to find the balance for yourself. Read from the internet and test different methods. Be critical.
BUT since you want strength and enhanced performance, I once again recommend you to atleast consume carbs pre and post workout. If you are having a long exercise (more than an hour) I'd suggest to have some carbs+protein during the exercise as well. Post workout carbs are the most important here. They are the key to recovery, performance and muscle building.
2) Resistance Training
B: Ok, what does RM mean? Also, what should the weights be -- should I go to the maximum that I can handle or light weights?
C: Hmm, so each day pick a different compound exercise and a few accessorial exercises?
RM is Relative Max. If something is 3RM, it's the heaviest weight you can handle for three reps without failing.
The weights depend. I recommend you to get heavy weights, but if you are new to weight training, I'd suggest to start with lighter weight and work on TECHNIQUE. Then build up. I wouldn't recommend maxing out every workout, but the weights should be close. Like having only one or two reps left in the tank (example: do exercise for 5 reps with weight you could do 6-8 reps). That's for the main lifts. Assisting exercises could be like 6-12 reps with lighter weight. A weight that you can handle atleast for 6-8 reps. No need to go to failure every workout.
C: Not necessarily. Once again, there are many options. You can split your workout through the week, or you can do a full-body routine 3-4 times a week. Full-body would consist of 4-6 exercises you would do (you can also cycle the heaviness of the exercises), or then you can do Upper body/lower body split, in which you would do the same workout twice or once a week, switching lower and upper body every other workout. The there's the style many of us do here in exrx: one or two main lifts per workout. Mine at the moment is four workout days split: Squats, Overhead Press, Deadlift, Bench Press. I would suggest you to keep the same exercise for atleast a couple of workouts, especially when you are new to weight training. I stress this again, it's important to learn the technique of the movement first.