If you aren't already comfortable with the way you approach dating, you might want to consider trying out some of these suggestions to see if they prove helpful.
Be initially self-centered. Self-centered doesn't mean selfish. It means to be more focused on whether or not you like the person you're dating than whether or not they like you. Pay careful attention to what you are feeling and how your emotions react to what your date does. If you are feeling uncomfortable, that may be a sign that this should be the last date with this person.
Have modest expectations. Chances are good that your date will be nice but nothing special. Relax and enjoy the dating process. Try not to need it to become something other than what it is. If you can find something enjoyable about your date you won't go home sad even if it doesn't set off fire alarms.
Expect to be rejected some of the time. You can't be everything to everyone. Rejection early on in a dating relationship is not personal, but rather is all about what is happening in your date's mind. If someone rejects you they are doing you a favor as they are ending an interaction that won't work out sooner rather than later. You are now free to find another relationship that will work out.
Put your best foot forward. You don't need to be different than you are (taller/shorter/thiner/smaller/hairier/smarter/etc.), but you do need to wash yourself, put on deodorant, dress nicely and shine your shoes. Looks are very important. They play a role in sexual attraction (for you and for your date) and if your partner's looks don't match up with what you like (or vice versa), no sparks will fly. Bearing this in mind there really are people out there who are attracted to every shape and size person. How you carry yourself is ultimately more important than how you look. If someone is hung up on a particular size/shape that you don't have, they are not worth your investing energy and emotions in.
Have a plan. It's nice to have a plan for the evening defined in your head (where you'll go, what you might eat) so that your date isn't forced to figure things out for you both at the spur of the moment. This being said, some partners will prefer spontaneity and some will appreciate the structure. Go with the flow and what works best for each unique situation.
Have fun. You're out on a date to enjoy yourself and see what can develop in the moment. Don't burden the situation with neediness from your past or hopes for the future. Be present in the moment and see what fun you can find.