Short Sweet Tips from a guy who knows a thing or two about Romance#1: Make sure you can tolerate the person writing the other end of it. If they drive you mad, it'll reflect in your writing subconsciously. Conversely, this also applies if you have a crush on them: You'll be more naturally inclined to write romantic gestures towards them subconsiously. There's a lot of things you can still manage to do with someone you vehemently dislike: Writing romance between your characters is not generally one of these things.
#2: Make sure your character has motivations and goals outside of romance, and that those goals generally occupy most of their thought time. It's sweet when a person is working and notices something that reminds them of their lover, or heart wrenching when they are separated and suddenly realize how alone they feel without the other person, but if your character has no independent life of their own--that is, if the romance
subsumes their very being--this isn't just incredible unhealthy and obsessive, it's ludicrously boring and doesn't go anywhere.
#3: Whatever good advice applies to relationships in real life applies to relationships in writing, generally. So 'forced sex'ing a person you met ten minutes ago? That's not romance. That's extremely illegal and at least a little immoral.
On the other hand, realize love comes in more flavours than just the typical boy-meets-girl romance that Hollywood adores. There's coworkers who have the spark but never act on it, there's jovial brotherly love, there's the love of a mentor for their student... Basically what I'm trying to say is that love is not confined to how you physically act towards another person, but purely about how you feel towards them. A shy, reclusive character who shares heartfelt poetry and who's idea of a romantic time is simply being in the same room with the other person is just as much in love as the person who puts a great deal of emphasis on cuddling, touching, hugging, and so on.
#4: No relationship is perfect but don't force cliché, nonsensical, attention whoring conflicts, especially in a group role play. It doesn't have to be about the relationship 24/7 and really shouldn't be as referenced in point #2.
#5: Arguable one of the most important pieces of advice about love in real life or in a fantasy:
Make sure the characters are still friends. In fact, most of the time, while they might share the occasional flirt, the most natural relationship is the one with the least amount of presence most of the time. Everybody knows Joel and Sally are dating, they don't need it reinforced every single time they meet with some passionate kiss and endless talk of how in love they are with each other: Let them
be who they are. Sometimes Joel and Sally are just sitting together eating food. Sometimes they're just beating off monsters or playing games just for the sake of it. Because the initial relationship made from love and acceptance of each other, wouldn't have started unless they got to know each other at least to some rudimentary degree and enjoyed what they saw in one another.
Your lover is also a best friend. One you should implicitly trust, because if you can't, that relationship is already boned. Speaking of which...
#6: Don't be afraid to let a relationship between two characters die or change. This is also normal and opens the door to more possibilities.
#7: Realize romance as a genre is like horror in that it doesn't stand on its own very well. If you're creating a romance story, think about another genre you can mix it with, because romance alone suffers the problem described in point #2:
There's no other reason for those people to exist and so it's very forced. This is why a lot of romance subplots are just that: Subplots, something that goes on in the background of a story. (Like Leia and Han Solo in Star Wars.) Or, if romance is a primary element, it's mixed with another genre, often comedy. This prevents emotional over-saturation, it lets the romance be cut with feelings of excitement in an adventure or intrigue in a mystery or so on and so forth.
#8: Specifically on sexuality: While sexuality can be a very complex, interesting thing to explore, be they dark urges that a character struggles with internally as a person, or the lack of any urges at all (asexual), or homoerotic urges, and so on, if your entire character's reason to exist can be described by their sexuality,
you're doing it wrong, start over. A person is not just a lesbian: Being a lesbian is a piece of who they are, along with several other traits that make up the essence of who they are and how they think and what they believe.
#9: Sex is not the ultimate expression of love. Stop listening to Bioware and Hollywood, really, it's not, anyone can do it, for any reason, and not call it love. Sex with intense feelings such as love is great, but sex is
not the ultimate expression of love, at all, just, no.
Don't make this your end game for the relationship. If your main objective to affirm a relationship is any kind of sexually gratifying action, then your relationship is, I'm afraid, predicated on rather bestial feelings, we inherited through four billion years of evolution, not love.
#10: Don't force it. Let it come as it may. If you're really looking for it, mention it with your partner (1x1) or to your group. It's perfectly okay to mention who is willing and who is wanting to have their characters look for romance, it's even okay to bat around with a little planning about potential scenes you can do together. Just make sure to do them organically, let your character do what would seem most natural in that moment. If character X does something character Y dislikes, defy your looseleaf script and let Y slap X. If someone else wants to enter the fray, let them, and remember all of the above points so your character has something to do other than obsess over someone all the time. It will flow easily and naturally if you keep orchestrating reasons why they would talk to each other,
and if they can be good friends... Well, there's the reason.
That's about it really.