It helps to observe body language. Don't look at this in isolation though, also pay attention on what is said while you are on the date and when you are walking together. If they ask a lot of questions about you then it is a good sign that your date is interested in you. This is also reinforced with the interest in the answers that you give. Eye contact is also a way of telling if some is interested in you and look at how close your date is to you. Frequent smiling and laughing are also good indications
Pay attention to physical clues from your date, but also pay attention to what they say during the date and while walking together. If your date is truly attracted to you, they will ask questions about you and will be genuinely interested in the answers. People will show attraction to someone by maintaining longer eye contact and staying close to their date when walking. Frequent smiling and laughing are also good indications your date is enjoying your company and is attracted to you.
When you date is approaching the end, make sure you keep these tips in mind. If you notice that your date does not want to leave, then it is a good indication that they are expecting a goodnight kiss. Move in a little closer to test their comfort level. If your date backs away, then take the hint that they are not ready for intimacy. Now if your date stands their ground, or maybe moves closer than they are definitely interested and such an instance deserves the attention of a kiss.
The initial kiss should be gentle. Remember less is more on the first kiss and will give the impression of respect for your date. Learn to kiss more lightly and slowly but with purpose. A little open mouth will do and do not go all the way too soon. Leave it to your date to set the pace and how long the kiss goes for. To leave a lasting impression, at the end touch their hand and leave.