As said by others, 0.5 mg should get you to a nice state of relaxation, without being benzo'd out, really. But, you could try 0.75 mg, if you want to be really nice and relaxed, and you might be a bit benzo'd out, but should be fine. Definitely no more than 1 mg, I'd say, but if you are just having like a low-key afternoon or evening or whatever, 0.75 mg to 1 mg would be alright. It doesn't really induce euphoria via its mechanism of action, but some say they do feel a very nice euphoria from benzo's (especially in the beginning of their personal histories with benzo's) - usually those with anxiety from the get-go feel this 'benzo euphoria'. But, for most people, a benzo is not going to get them 'high' per se, rather just let them be feeling nice, relaxed, relieved from daily stress, and a bit pleasantly apathetic. They are, after all, sedatives or tranquilizers, whatever you wish to call them, but they basically down you out. Just please don't be stupid about benzos, and dosing, because some inexperienced (and some experienced) benzo users will take some, not feel like they feel it, take more, and then lose all good judgment as to their condition very easily and very rapidly; benzo's alone will not kill you via overdose, even at really high doses, BUT they have the potential to fuck your judgment up at higher doses, which can lead to some very dangerous situations due to a lack of discretion on the user's part. That is one of their dangers; the other is the potential for addiction (or, even physical dependence without addiction), because benzo addiction can really, really fuck your life up.
I would stick to a designated dose of 0.5 mg to 1 mg, take it at once, and try to make sure you won't take more before you take any. Also, DO NOT drive or put yourself in potentially dangerous situations, at ANY dose, because you have no experience with benzo's and how they effect you, and in downing you out, they will effect your reflexes significantly. Just be in an environment where you are nice and safe, and ready to relax and tune out.