Becca, I also have to equalize for a couple of minutes to get past 15-20 feet of depth, then it's easy after that. For that very reason I'll descend feet-first for the first 15-20 feet, so I can kick up a little if my ears need it. Then I'll level out to horizontal for the rest of the descent, so I can see where I'm going. Unless, as Dr. Bill says, the visibility is horrible and I can't see 5 feet; in that case I'll usually descend feet first and level out at the bottom.
You'll find what works for you too.
There are a few things that can make it hard to descend other than being underweighted, and I did all of these at first: kicking with your fins below you (usually subconscious); holding too much air in your lungs even while you're breathing / "breathing off the top" (also subconscious); and having a lot of air trapped in your BCD or wetsuit at the beginning of the dive. The first two tend to improve with practice. The third one can be remedied by letting some water into your wetsuit while you're at the surface, and also by grabbing onto a hang line or anchor line and pulling yourself down just a few feet from the surface if you're diving from a boat. Once underwater, you can wiggle around a bit and use a couple of different dump valves to get the extra air out of your BCD and wetsuit. Once the extra air is out of your gear, you should be able to descend the rest of the way easily. If you know you have the right amount of lead from doing a weight check at the end of a dive in the same conditions/gear, you can try those tricks instead of adding more weight than you really need.