I don't use Reason but I know a thing or two about it and the process is basically the same except you should understand that Reason is a closed DAW. By that I mean, it cannot host third party plugins. I think they are toying with the idea for the new Reason or maybe even the latest version supports VST but I don't think 5 does. Don't quote me, do your research, but Reason has notoriously been a closed DAW for many years. There are some advantages to this and some disadvantages. Regardless, Reason is plenty to start learning to make "beats" or whatever else you might want to make. So here goes nothing:
1. What a question...
Well, there's a million ways to go about making music on the computer/electronically. So without sticking to that idea and being completely vague, I will give you a rundown of what I know best... my own process. I use Ableton Live but the process shouldn't be too different. I think you can record in Reason and if so, then the process is nearly the same minus the plugins. Just to be clear, I make electronic music which is almost always MIDI based.
So... I use Live to create MIDI clips which are played through either software instruments or hardware instruments. Software instruments are easy because they are hosted inside of the DAW. In your case, you would be limited to Reason's native instruments, which are fine instruments. If you plan on using synths, I would highly recommend investing the time in learning synthesis. It will expand the possibilities of your music tenfold, instead of relying on finding the perfect presets. After a while you will find that presets can work but that you will spend a lot of time searching for the "perfect" preset and even then you will probably make compromises between the sound you had in mind and the sounds available as presets. Simply put, try to learn to make your own sounds from scratch which means... learn synthesis.
These MIDI clips are then arranged to make sequences of sound. This is the core foundation of making a tune. Sometimes, you might want to use hardware based instruments. Here's where things get interesting. If you are using a fairly modern hardware synthesizer... for instance, an Access Virus, you will have MIDI built into it. In this case you will need to connect your MIDI ports on your synth into the MIDI ports on either: A. your audio interface (if it supports MIDI) or, B. an entirely separate MIDI interface. There are also other options, I recommend the M-Audio Uno for connecting one synth at a time via USB. Quite simple to use. A high end audio interface should have MIDI built in.
If you are controlling vintage analog synths which came out before the release of MIDI... early 80's synths and older, you will need a converter of some kind. Old analog synths didn't use MIDI for control signals, they used a protocol called CV (control voltage) which controls the synth not by MIDI events but rather by... you guessed it, control voltages. Different voltages equal different signals basically. If you opt to use a vintage synth which lacks MIDI you will need to convert CV signals into MIDI signals to play nice with your MIDI based setup. Look into Kenton or Doepfer for converters.
Once you have your tune sequenced with all your tracks running you will probably want to experiment with effects. Being a guitar player, I'm sure you're familiar with the idea of effecting audio signals. I won't go too deep here but basically you can experiment with effects. You should learn your effects inside and out, it is largely what separate amateur production from a more professional sound... though that is quite a blanket statement in and of itself since it all adds up to make the final product. My point here is, learn your effects, it will make a crucial difference in the long run between churning out sub par mixes and creating great mixes. This won't happen overnight, it's a process of refining and understanding your own process of engineering.
Once you have everything the way you like it, make your final mix. That is, do any tweaks you didn't do before. Make it perfect. Make it the best it can be. A few tips here if you are serious about taking your music to commercial level: Leave your master fader clean. Don't throw effects on it. People might tell you to limit that channel for loudness. Don't. Not if you intend to get your tracks mastered anyway. The mastering engineer will do this for you, it's his job. Don't try to step on his toes by doing something for him, you may just create more work for him and yourself in the long run if he decides he needs to undo it or change settings. Leave your master fader clean. And try to keep it at unity (zero) if you can... Which you should easily be able to do if you practice proper gain staging. Then basically once you have this mix ready, you will send it off to the mastering engineer or you can master it yourself if you know how and are confident in doing so.
That's the process in a nutshell. If you want to record in instruments other than MIDI based instruments, it's even easier than using MIDI. Simply arm it to record and run it through your audio interface either by being mic'd up or by using your line inputs. Then add these audio recordings into your sequences. Voila, now you have a mix of "real" and MIDI based instruments. That's it pretty much. An extremely shortened write up of the process but hopefully that clarifies a few things.
A few things to take away from that gear-wise would be: Understand that in order to do proper mixes you will proper monitoring. I have the exact same headphones you listed and they are decent for what they are. However, I personally, would advise not only using them to mix. Invest in some proper studio monitors if you intend to make this music commercially acceptable. I'm not saying it's not possible to make good mixes on headphones, but there is a reason pros don't just buy headphones and call it quits there. There are reasons people invest thousands in proper monitoring setups. On that note as well, you may want to look into acoustic treatment for the room you mix/record in. That's a whole other can of worms, but look it up if you feel you are getting inaccurate translations of your mixes.
Finally on the gear thing... last thing I will say for now anyway is: The audio interface in many ways is the crux of your studio. Don't skimp if you can. Know what you expect to get out of it and find one that will serve your purposes well. If you like the one you have (I am unfamiliar with it and I haven't Googled it) then use it and know it well. If you need and expect more from your interface, find something that will last you a while because you will want something effective that you can count on without needing to upgrade every time your productions hit a new level.
Okay...
2. Hmm... best tips... Well, some of the gear tips I listed above would work in this section. But on a more mental level, understand that this is a process. It takes time to get mixes you are happy with. It all depends, like anything, how much time and dedication you put into it. If you are just making it for fun and you could care less about mixes then my #1 tip would be, remember to have fun. Make music that makes you happy. Learn what interests you and follow that as far as you can. You will probably get into all different aspects of production the more you dig and it can be overwhelming all at once to try to learn to mix/master/arrange etc. all at once. Instead, focus on what makes you happy and do it until you know it well. The more you explore the more you will learn and in a few years when you look back on where you were today you will be amazed. Production is very much the same thing as learning an instrument. You need to learn systems of understanding and you need to learn how your tools work and when to use each one. Learn the basics, read a book or sign up at a music forum that is much better than this one. Find a community that will help you thrive doing what you want to be doing and don't be afraid to ask questions. It can get heady and technical at times but just remember why you are doing it in the first place.
That's all I can think of right now. Good luck.