You have gotten some good advice here, I just wanted to add my opinion on it. 1st of all, the best advice you have received thus far is to learn to manage your risk. You need to be 100% honest with yourself and ask yourself "how much can I afford to lose?" By "afford", I mean, how much money if you lost it right now, would you not lose sleep over? You have to only use money that is 'spending money' (so in other words after all your bills are paid). You have to consider Forex in terms of it being a business which does have unavoidable "costs" from time to time (losses). If you aren't honest with yourself about this true LIMIT and hold yourself to it, you will fail everytime.
So, let's pretend (just for illustration purposes) that you make $600 per week, and after you have taken out all the money for paying your bills you have $150 of 'extra' money. Do you need some of that for 'fun money'? Like a date, going out with friends, buying a new video game or whatever? Okay, let's say that you don't. Let's pretend that this weekend you have no plans and you don't need a new video game or whatever. So you have $150 to spend. BUT...would you lose sleep if you lost $150, would you have a little cry, or a little panic attack or whatever? The point I am driving at, is the money that you risk needs to be truly inconsequential to you - especially at first. This is if you are trading live obviously, which I am assuming that you are, but even if you aren't - my advice is to treat your demo trading as realistically as possible. That way when you start your 'live trading' you are used to risking the realistic amounts of money that your live account is going to be risking. One of the most important aspects of being successful at Forex is learning to control yourself!
So, now let's pretend that you have answered me that out of your $150, you truly feel comfortable with 'losing' $50 of that. Then this is the amount that you should limit yourself to, for the entire week. You have to be strong. No one else can reign you in and make you control yourself. Because if you lose that $50, you might say to yourself, well, I still have $100 more, and I could win my $50 back - but if you said you were comfortable with losing only $50 - you must stick to that! Trust me, this is important. So, you need to calculate your risk for your trade(s), and there are risk calculators out there if you don't know how to calculate lot sizes yourself. If you want to know more, just ask and I'll recommend my personal favorite.
You mentioned the EURUSD pair, is this the only pair that you trade? If it is, then just remember that there is not always a good trade present and sometimes you will have to sit on the sidelines and do nothing (like when its in consolidation or violently swinging around...too much volatility, it's its not headed in one direction or another - is not a good thing!) I think it is good practice to focus on one pair, especially when trying to learn and master price action, but it can be difficult for excited newbies to NOT make a trade. If I misinterpreted what you said (and you are not limiting yourself to EU), then if I were you, I would scour the charts and look for only the most solid-looking trade, and limit myself to one trade at a time right now. Why not find the 'best trading opportunity' and invest in that one risk rather than half-assing it and splitting your risk among several trades (over-trading = sloppy trading and usually over-trading = over-risking). You are right that you need to control your emotions and greed, and all of the above steps that I mentioned are crucial to doing that!
You mentioned missing London open when you trade, but I would recommend trading the daily time frame and checking in just after the NY close (using NY close candlestick charts). This is a good approach for people with limited time, or anyone who wants to actually make money This works best if you trade price action, and I'm not sure what system you use. Well, I hope that you find some part of this rant helpful...good luck!