1. Is he saved? He must be a Christian and love God. Besides the obvious dangers of being unequally yoked, it is important that he has a heart that wants to follow to Lord. If you are both focused on Christ you'll have a much better relationship.
2. Do I trust him? You must equally trust each other 100%. Without trust, a relationship will crumble. It's important to begin a marriage on the right foot, and that means entire trust for each other, in every area.
3. Am I comfortable and able to be myself around him? You need to be comfortable and at ease with each other. So important, but somehow forgotten too often. Life isn't a big fancy date, sadly! Spend time with each other on a daily basis and make sure you are compatible doing even the most mundane of chores. You'll be spending a lot of your married life doing normal things together, so it's important you still like each other without the roses and candles present!
4. Does he respect me? He must respect you and treat you right. Just because wives are to be submissive, that doesn't mean you should be treated like a doormat. It's important that you can openly discuss things with equal respect for each other. He needs to respect your opinion and feelings as a grown woman. Just because he makes final decisions doesn't mean he should bulldoze either. He is supposed to be your husband, not a dictator. I think respect is high on the list when considering marriage. Don't marry a bully.
5. Can we agree on things? You need to be able to come to agreement on important matters. If it means coming to a compromise, or agreeing to disagree in some cases (without resentment or other aftereffects). Talk about all of the important things before marriage and you'll escape some misunderstandings and arguments afterwards.
6. Are we a team, can we work together? It's important that you're both on the same page. (This kind of ties in closely with the point above!) You want 3 kids maximum, and he wants at least 8. You want to start a family right away, but he wants to wait awhile. You expect one thing, while he is off planning something else. You can easily see how this could cause some pretty serious problems later on! It's important that you stand together as a couple, with similar goals and plans for the future. So don't just talk about the here and now, talk about the future! Sure, plans change, people change, the future is full of surprises! But it's a good idea to start off a marriage with both of you on the same page.
7. How do our families feel? (This might not apply to everyone depending on your situation. If not your family, then consider asking someone else you highly respect, such as a friend, or pastor.) Many times others can see things that you can't. Ask for an honest opinion on your relationship and be open to what they have to say. They probably have some good insight and advice to give you.
8. Do I desire him? (And opposite!) So important! Many times I've seen christians (especially girls) get too wrapped up in making sure all their boxes are checked but totally forget about attraction. You'll be with this guy for the rest of your life. He needs to be the one to put butterflies in your stomach girl! Attraction could be that one thing that keeps you coming back to each other when you are failing in every other area. It is important you feel desire and attraction towards him.
9. Is this what God wants? Obviously so important! Take time to search your heart and spend time with The Lord to decide whether it is God's will or not. Ask Him to show you if it is His will, and wait for the answer. Open your heart to the Holy Spirit and ask for discernment in your relationship!
10. Is this what I want? You know what, it really is important whether or not it is what you want! I think it is extremely disrespectful of your significant others feelings, if you say yes without being 100% sure that this is what you want. You should never feel rushed or forced to settle for less. Search your heart and try to decide is this relationship is what YOU want for the rest of your life! Ask yourself, "am I happy? Truly, 110% happy?" If there are issues bugging you, or something specific tugging at your conscience, don't keep it inside. It's important to express your concerns, and talk everything out. When you go down the aisle, you need to have perfect peace in your heart, and know without a shadow of a doubt that this is the person you want to marry!
Like I said in the beginning, these are just a few points that came to mind. They aren't in any special order and I'm sure I left a lot of important stuff out! If you are in a relationship feel free to leave your thoughts and extra points in the comments below! I will edit this post later on to add any good points you guys bring up. :-)