1. You can not do enough trip planning
1a. What travel company should I use? That depends on your budget. We found Born Free in the Denver area worked for us. They offer reasonably priced package tours all the way to full on custom tours. We did a custom tour. With out a doubt use Born Free!
2. A lot of what you will read is wrong. Dont assume everything here is right. The color of your clothes DOES NOT matter. You are not hunting with a rifle. There is so much game you will see animals no matter where you go.
3. Pack light! We had a singe soft-sided duffle limited to 33 lb. for the whole month. That meant safari clothes or so we thought. Getting laundry done, with the exception of underwear was easy. Buy silk or quick dry undies and you are good to go. Our weight limit was based on very small bush plane capacity constraints.
We were also allowed one carry on so I bought a backpack camera bag which worked well to hold my camera body and lenses. BUT Get a HD Video camera that uses tape. LEARN TO USE IT BEFORE YOU GO :-) You want tape so you can pack them away as you fill them up. Film EVERYTHING. For ultimate safety mail them home in batches or keep them in your carry on. The new disk drive cameras are a pain in the butt on a long trip. Video tells the story of your trip. Have you ever heard the barking of 10,000 zebra? I have and I amaze my friends with the DVD my sister in-law made when we got home. My sister in-law Linda took all the video. When the lion kills the wildebeast or the 18 foot croc kills a wildebeast do you want a static image or the real deal.
4. We think the last two weeks of June and the first two weeks of July are best. There are two rainy season and you want to avoid both. This will depend on where you plan to go. We went every where to be sure we saw the great migration. Around June they are often halted on the south side of the Grumeti River, which blocks their migration north. They congregate there, in the Western Corridor, often building up to an incredible density before a series of panicked crossings ensue - one animal crosses and the rest rush across. This is the annual feast for the Grumeti River's large crocodiles.